# Craftsman self-propelled mower is an "Oil Gusher"



## TBm (Feb 10, 2011)

Hi, all ==

This is my first post here. I've been keeping a 12-year-old Craftsman self-propelled mower alive, but have run into a problem. Here are pictures of the model; please note that the motor has an *OIL PUMP*.










At the end of last year's mowing season, I had to flip the mower entirely upside down to work on the gear box. I tried to empty all the oil prior to flipping the machine, but a lot more drained out while it was upside down... It seemed to be coming not from the oil fill spout but from the top of the engine, under the plastic pull rope cover. 

When the repair was complete, *I refilled it with oil* and gave the gearbox a ten-minute test run. No problems, BUT there continued to be new oil spots on the garage floor where I store it...

I put the mower out in the yard and just let it run to empty the remaining gas from the tank and carberator as Winter prep. When I went out to check on it (while running) it was smoking quite a bit. I noticed a LOT of oil had collected in the circular depression in the sheet metal deck around the motor. See image below:











While it was running, I unscrewed the oil filler cap/dipstick. It almost blew off. I'm not sure if that amount of pressure is normal because I never took the oil cap off while the mower was running before.

I had refilled wth oil after the gearbox repair, but 20 minutes of run time and the dipstick indicates "ADD". It appears the oil is exiting the motor from high up under the plastic covers. See image below:











*Any ideas on what I need to to do to straighten this out?* 
1. Could flipping it upside down for a couple of weeks cause a BLOCKAGE?
2. Is there something I need to do regarding THE OIL PUMP?

HERE'S A LINK to an EXPLODED VIEW of the engine (you can zoom in on the image).

Any help is MUCH appreciated. I need to get this sorted out before Spring.

Tom


----------



## 30yearTech (Sep 14, 2006)

Check the air filter element, if you did not remove it when you flipped it over it may be saturated with oil. The oil could be coming from the oil breather that is located on the top of the engine block. If the air filter element if full of oil, you may get oil to seep out of it for quite some time. Make sure that the oil dipstick tube is in tight and that it has no damage.


----------



## geogrubb (Jul 28, 2006)

I think you will find the sump gasket has failed, when it was turned upside down the crankcase breather became blocked, the built up pressure forced a leak at the sump gasket, I think you will find the bolts loose on the sump. While it is running watch for oil to leak at the gasket below and slightly to the left of the carb. Have a good one. Geo


----------



## 30yearTech (Sep 14, 2006)

geogrubb said:


> I think you will find the sump gasket has failed, when it was turned upside down the crankcase breather became blocked, the built up pressure forced a leak at the sump gasket, I think you will find the bolts loose on the sump. While it is running watch for oil to leak at the gasket below and slightly to the left of the carb. Have a good one. Geo


While that is certainly a possibility and something that should be looked at, the Vector series engines did not have much of a problem with the sump gasket leaking like so many of the TVS and LEV series engines. Those series engines had issues with the gasket developing leaks in the area of the oil pump, particularly when the bolts became loose.


----------



## TBm (Feb 10, 2011)

30yearTech said:


> Check the air filter element, if you did not remove it when you flipped it over it may be saturated with oil. The oil could be coming from the oil breather that is located on the top of the engine block. If the air filter element if full of oil, you may get oil to seep out of it for quite some time. Make sure that the oil dipstick tube is in tight and that it has no damage.


Thanks. I will check that dipstick tube. There IS oil in the paper filter, but not too much, and just along the edge nearest the breather hose where it enters the air filter canister. It's so doggone cold here that I haven't pulled everything off the top of the engine yet. 

Is the OIL BREATHER just an opening in the top of the engine block? Is there likely to be some kind of filter element up there, or just the breather hose running down to the air filter canister? #6 on the schematic says "Breather Element" and #12 says "Breather Hose". *Can you tell me what the Breather Element looks like?*

What you describe sounds right, but what would cause _almost all_ the oil in a full crankcase to move UP and out of that oil breather? Seems like something's blocked...


----------



## TBm (Feb 10, 2011)

geogrubb said:


> I think you will find the sump gasket has failed, when it was turned upside down the crankcase breather became blocked, the built up pressure forced a leak at the sump gasket, I think you will find the bolts loose on the sump. While it is running watch for oil to leak at the gasket below and slightly to the left of the carb. Have a good one. Geo


There DOES seem to be a blockage (see my previous post) and it WAS turned upside down for quite a while. I can't tell for sure, but the oil appears to be exiting the engine higher up than your description of the sump location. Two questions:

*Q1. How would I unblock the breather?* Is the idea that oil sludge from the bottom of the crank case flowed into the #6 Breather Element while upside down...? Is it something that can be simply blown out with compressed air?

*Q2. I can't find anything on the schematic that refers to "Sump".* I find the Carburator at #380 and have tried working from that location, but no dice. Do you see anything that looks like it?

Thanks


----------



## 30yearTech (Sep 14, 2006)

TBm said:


> Is the OIL BREATHER just an opening in the top of the engine block? Is there likely to be some kind of filter element up there, or just the breather hose running down to the air filter canister? #6 on the schematic says "Breather Element" and #12 says "Breather Hose". *Can you tell me what the Breather Element looks like?*


No, it is an opening with a cover screwed down over it. Inside the cover is a check valve (ref # 11) in the IPL and a foam filter (Ref # 6). The breather is vented via the breather hose into the air filter box. 



TBm said:


> What you describe sounds right, but what would cause _almost all_ the oil in a full crankcase to move UP and out of that oil breather? Seems like something's blocked...


The oil can't completely drain from the crankcase through the breather when the engine is running, but if you had it turned upside down long enough, the oil can completely drain from the crankcase through the breather. It may have just drained and collected underneath the flywheel or shroud on the top side of the engine, and drained down once the mower was turned back over. If there was a lot of debris or sludge in the crankcase then it's possible that the check valve could be plugged. Excessive pressure in the crankcase could cause one or both of the seals to be blown out, and or the sump gasket.



TBm said:


> There DOES seem to be a blockage (see my previous post) and it WAS turned upside down for quite a while. I can't tell for sure, but the oil appears to be exiting the engine higher up than your description of the sump location. Two questions:
> 
> *Q1. How would I unblock the breather?* Is the idea that oil sludge from the bottom of the crank case flowed into the #6 Breather Element while upside down...? Is it something that can be simply blown out with compressed air?


To clean out the breather, you would need to remove the flywheel (ref # 90) and take the cover (ref # 7) off the oil breather to clean it out.



TBm said:


> *Q2. I can't find anything on the schematic that refers to "Sump".* I find the Carburator at #380 and have tried working from that location, but no dice. Do you see anything that looks like it?
> 
> Thanks


What we are calling the "sump" is listed on the IPL (ref # 70) as the mounting flange.


----------



## TBm (Feb 10, 2011)

MAN! THIS INFORMATION IS VERY HELPFUL! THANK YOU



30yearTech said:


> ...it is an opening with a cover screwed down over it. Inside the cover is a check valve (ref # 11) in the IPL and a foam filter (Ref # 6).To clean out the breather, you would need to remove the flywheel (ref # 90) and take the cover (ref # 7) off the oil breather to clean it out.


If the filter (#6) is foam, can I remove it, soak it in a soapy solution to clean it, and then reinstall? 




30yearTech said:


> The oil can't completely drain from the crankcase through the breather when the engine is running, *but if you had it turned upside down long enough, the oil can completely drain from the crankcase through the breather.* It may have just drained and collected underneath the flywheel or shroud on the top side of the engine, and drained down once the mower was turned back over...


I think that's EXACTLY what happened, and it explains why I kept seeing new spotting on the floor AFTER the gearbox repair. Of course, I refilled it with fresh oil, and later I ran the gas out of it. At that point most of the newly refilled crankcase oil exited the engine in just 10 minutes of running (which leads to your next comment, quoted below).




30yearTech said:


> If there was a lot of debris or sludge in the crankcase then it's possible that the check valve could be plugged. Excessive pressure in the crankcase could cause one or both of the seals to be blown out, and or the sump gasket.


I see the upper oil seal at #20 and the bottom oil seal at #75. There's no leaking at the bottom, so that one's okay. I'm hoping the upper is good, too. 

In my original post I mentioned how the dipstick/cap nearly BLEW OFF when I removed it while running. I take that as an idication that there was a LOT of pressure in there, and also that the seals are probably okay, because if the seals really were blown, there'd be no pressure build up... *What do you think? Is this just Pie-in-the-Sky wishful thinking?* :freak: 

*Once I remove the flywheel, is there a lot more work in removing the #20 upper oil seal and replacing it?* _Or can I just grab it with needle-nose pliers and just pull it up and out?_ 




30yearTech said:


> What we are calling the "sump" is listed on the IPL (ref # 70) as the mounting flange.


Thanks for clarification. I misunderstood geogrubb's instruction. Either of you, please correct me if I'm wrong: geogrubb was asking me to inspect the major gasket line that appears in my last photo. There appears to be no leakage at that mating line.


----------



## geogrubb (Jul 28, 2006)

You are correct, I was referring to the main gasket, 30Year is probably right with the oil in the debris under the shroud, also check the gasket/O-ring where the dipstick tube enters the block the crankcase pressure could have forced it out of place. Have a good one. Geo


----------



## 30yearTech (Sep 14, 2006)

TBm said:


> If the filter (#6) is foam, can I remove it, soak it in a soapy solution to clean it, and then reinstall?


Yes, you can clean it with soap. I would recommend a dish washing liquid as it breaks down the oil very good.



TBm said:


> In my original post I mentioned how the dipstick/cap nearly BLEW OFF when I removed it while running. I take that as an idication that there was a LOT of pressure in there, and also that the seals are probably okay, because if the seals really were blown, there'd be no pressure build up... *What do you think? Is this just Pie-in-the-Sky wishful thinking?* :freak:


The seals are most likely fine, but they are there to keep the oil in, pressure in the crankcase can force oil past the seals, or cause them to come out in some cases. 

There are pressure pulses in the crankcase when the engine is running, and could have been caused by the breather being full of liquid, so I would not be surprised that the dipstick blew out when remove while the engine was running. I would suggest never removing the dipstick while the engine is running. 



TBm said:


> *Once I remove the flywheel, is there a lot more work in removing the #20 upper oil seal and replacing it?* _Or can I just grab it with needle-nose pliers and just pull it up and out?_


Unless the seal is loose or has come out, they will need to be pried out. I would suggest a good visual inspection to see if it appears to have been leaking, before replacing.



geogrubb said:


> You are correct, I was referring to the main gasket, 30Year is probably right with the oil in the debris under the shroud, also check the gasket/O-ring where the dipstick tube enters the block the crankcase pressure could have forced it out of place. Have a good one. Geo


I am pretty sure that on VLV (Vector) engines, the dipstick tube treads into the crankcase. I don't think they are held in with a screw like on most other Tecumseh engines, so they should not come out, even if there is pressure in the crankcase.


----------



## TBm (Feb 10, 2011)

You guys are FANTASTIC. Thank you for all this helpful advice. It may still be a few weeks before the garage thaws out enough for me to attack this problem, but when I do, I'll report back. I feel very confident in undertaking the job thanks to your insights.


_I did not receive an email notification of 30yearTech's post at 4:38pm yesterday, so if I fail to respond right away to any additional posts, it'll be because I didn't receive an e-notification. I'll check in on the thread when I can._


----------



## TBm (Feb 10, 2011)

*GOT A WARM DAY, so I jumped in. Need more advice.*

Weeks later, I finally got a day of mild-weather so I dismantled the top of the motor.

Here’s the link again to the IPL (ILLUSTRATED PARTS LOOKUP)
_(If your browser shrinks it to fit your screen, just click on it to zoom to full size)_

Removed the FLYWHEEL (IPL #90). I find a lot of oil on the sheet metal BLOWER HOUSING BAFFLE (IPL #25). I had refilled the crankcase with fresh oil before attempting to run the gas out for winter prep; the oil atop theBlower Housing Baffle appears to be a MIX of old cooked-on sludge and the new honey-clear oil. See below.











Cleaned things up a bit. See below.











Removed the BREATHER COVER and GASKET (IPL #7). The gasket was stuck on very well, so I don’t think it had been leaking. Inside the breather space I find no sludge. The oil appears to be just the new, fresh oil. The BREATHER ELEMENT (IPL #6) is oily but does not appear to be blocked. I will soak in a solution of dishwashing soap and water as recommended. 











The green CHECK VALVE (IPL #11) is a very flexible synthetic cap/flap covering the six holes of the tan plastic BREATHER VALVE BODY (IPL #10). The Check Valve appears to be undamaged and is highly flexible. The Breather Valve Body holes do not appear to be blocked. 











The TOP OIL SEAL (IPL #20) appears (to me) to me to be UNdamaged.











Below is a picture showing the clean oil in the breather housing, and the expelled oil on the SIDE of the breather housing. The breather cover gasket seems to be in good shape, but the oil all seems to be running down from that height…the height of the *breather cover* or the *top oil seal*… The first picture in this series shows oil on TOP of the Breather Cover...











The Oil Filler tube THREADS INTO the crankcase. It doesn’t appear to be leaking at its threads. Here’s a photo of the side of the engine after I had already wiped off a bunch of the oily mess. Before wiping, everything looked like the area to the left of the fill tube, and it appears to have run down from the sheet metal Blower Housing Baffle above. See below.











*BIG QUESTION #1: WHERE is the oil exiting the system? *

*BIG QUESTION #2: WHY is the oil exiting the system?*

*Is the top oil seal leaking?* It appears (to me) to be undamaged and intact… This engine does have an *oil pump*, but I'm hoping that's not the issue (I'm not experienced enough to work inside the engine). HELP.:freak:


----------



## 30yearTech (Sep 14, 2006)

It looks like it may have been leaking at the area indicated in this picture. Otherwise I can't really see anything obvious in the pictures posted.

I would suggest that you clean it all up, and either seal this cover with high temperature silicon sealant or replace the gasket with a new one. Then make sure the engine is NOT overfull of oil and run the engine and see if there is any further oil leaking. 

I think what might have happened, is this area filled with oil from having the engine tipped. Then when you flipped it back over and started the engine, there was too much oil in the breather that had not drained back into the crankcase. The excess oil could have prevented the breather valve from operating properly causing pressure in the crankcase and oil to blow out.


----------



## TBm (Feb 10, 2011)

30yearTech said:


> It looks like it may have been leaking at the area indicated in this picture. Otherwise I can't really see anything obvious in the pictures posted.


Thanks for your comments and the image. I cleaned and inspected the gasket as you suggest, but don't see any indication of a leak at the points suggested. It appears (to me) to show good solid contact along the entire mating surface. See image below:













30yearTech said:


> ...either seal this cover with high temperature silicon sealant or replace the gasket with a new one.


If reinstall AS IS, can I just screw the cover back down (3 screws hold it on) or do I have to get some gasket sealer and apply to the engine's mating surface?




30yearTech said:


> Then make sure the engine is NOT overfull of oil and run the engine and see if there is any further oil leaking.


Two seasons ago I DID accidentally overfill with oil. Never have been able to read the dipstick properly on this machine. IS THERE A DRAIN PLUG ON THIS THING? I've never been able to find one, so I end up flipping it upside down to drain it, but that's causing THIS problem...




30yearTech said:


> I think what might have happened, is this area filled with oil from having the engine tipped. Then when you flipped it back over and started the engine, there was too much oil in the breather that had not drained back into the crankcase. *The excess oil could have prevented the breather valve from operating properly causing pressure in the crankcase and oil to blow out.*


So if the breather can't breathe, the crankcase builds too much pressure. That sounds right to me, but I can't figure out FROM WHERE the oil is blowing out. I don't think it's blowing past the breather cover gasket. I'm thinking it must be the upper oil seal, but it doesn't appear to be broken...?

*Is this what's supposed to happen? * Per the image below, oil blows up out of the crankcase, past the soft green check valve (a) flows through the filter (b) and then runs back down into the crankcase via the little vertical drain hole (c)? Drain holes are at the red circle locations. I pushed a thin wire down each hole and all appear to be clear of obstructions. I have no idea what the purpose of area (d) is? It's totally enclosed/isolated and there's a small hole at the red circle...










30YT, what do you think about that upper oil seal? It looks undamaged to me, but there was oil ON TOP OF THE BREATHER COVER. That seems to point to the seal as being the oil's exit point. Could it allow oil past if extreme pressure built up in the crankcase (per your idea above)? Could oil blow past a good seal under those conditions?

Remember, I did overfill it once (or more!). Maybe that pressure weakened the seal?
*How difficult is it to get that seal out of there, anyway?*


----------



## 30yearTech (Sep 14, 2006)

I really don't think it's the seal, there is minimal area around the crankshaft journal for oil to flow. If the seal looked damaged or was pushed out of the crankcase, then oil could leak out, but the seal does not look loose or damaged. The area I indicated in the picture is also the area which has the least amount of clamping pressure from the mounting screws, oil can push past this area. I would definitely use some sealer when reassembling this cover. Oil is not supposed to flow up past the breather valve (A) only crankcase pressure. There is usually never much actual oil in this area, vapor mostly which will condense and flow back into the crankcase via the drain holes. 

Since there is nothing that jumps up and points to itself as an area of concern. I would still recommend a little clean up, and some sealant to insure there is no leak from the cover. Then make sure the engine is not overfull of oil. 

When draining the oil, don't flip the mower upside down, just rest it on it's side with the air filter side facing up. let the oil drain out the fill tube. Try not to turn the blade while it's in this position. It takes about 20 oz. of oil to fill the crankcase. More then this amount can cause issues.

Unless there is a crack in the crankcase somewhere that's not readily visible, I don't think you will have a leak, once the breather cover is reinstalled.

Best of Luck...:thumbsup:


----------



## TBm (Feb 10, 2011)

30yT ==

Thanks a LOT. I'm sure you're right about the area near the crankshaft _journal_ (I learned a new term) being the likely leak source due to the location of the three mounting bolts. And THANK YOU, THANK YOU, THANK YOU for telling how to drain this thing without _all the drama_.  

Three quick questions before I drain the oil, refill and reinstall the breather cover as you suggest. 

QUESTION X: You wrote earlier, "*...either seal this cover with high temperature silicon sealant or replace the gasket with a new one.*". I found Permatex® 1372 High Temperature Form-A-Gasket® Sealant and intend to pick some up locally if it's the right sealant. If it's NOT right, could you pick the right one from this Permatex product page. 

QUESTION Y: Based on the picture below, I don't see any breaks in the gasket. I do see tiny bits of (what appears to be) dried gasket sealer stuck to the indented track where the gasket is compressed by contacting the engine surface. *Do I need to clean that sealer off somehow? I hope not.* I don't think it'd be possible without damaging the gasket, and I'm hoping new gasket sealer will just squash and fill in any tiny gaps. 

QUESTION Z: Assuming I leave the existing gasket in place, do I just clean the top edge/surface of the breather housing and then apply a small bead (maybe 1/8") of sealant to the aluminum?


----------



## 30yearTech (Sep 14, 2006)

X: This sealant is fine.

Y: No further cleaning of the gasket is needed, it looks fine in the picture

Z: Yes, just a light coating not to heavy to insure a good seal when the plate is tightened down. You do not want a lot of excess sealer to be pressed out after the plate is tightened.


----------



## TBm (Feb 10, 2011)

I'm on it.

Thanks for every word of helpful advice. I'll report my results (fingers crossed).


----------



## TBm (Feb 10, 2011)

*Shoot Me Now*

Spring has sprung, so I spent the morning reassembling. Got it all back together (no leftover parts) after lying around the garage in pieces for months. WooHoo!

Manual says 27 oz of oil. I've never been able to read/trust the dipstick, so had been filling with 24 oz. Per your suggestions, this time I only put in 20 oz.

Started on the second pull, so I wrapped a piece of wire around the deadman to keep it running, and waited. *After a few minutes IT STARTED DRIPPING FRESH OIL DOWN THE FRONT OF THE ENGINE *(see picture below). 

It was dripping steady at about one-drip-per-second, and the drips were falling from the first cooling fin (closest to the crankcase).

It's very difficult to re-start. Acts like it's flooded with gas, though I haven't done anything to cause that. Just start it, let it run, turn it off. :freak:

I need to cut grass in a week. HELP!


----------



## 30yearTech (Sep 14, 2006)

Hard to tell from the picture where the oil is coming from. I would take the cover back off and have a look underneath the flywheel before you run it any more. You might be able to determine where the oil is coming from if you don't have to much spread all around. 

Is the breather tube where it attaches to the air filter open? If the hose is pinched excess pressure could build in the crankcase forcing oil to leak out.


----------



## TBm (Feb 10, 2011)

No, the breather tube to the air filter canister is completely clear.

I did not apply hi-temp gasket sealer to the mating line between the breather cover gasket and the engine. Please help me deterimine if that's the problem now. 

*Why I didn’t buy and apply the sealer:* As I understand it, the breather cavity does not FILL with oil. Crankcase pressure vents into the breather cavity, and just a little oil blows into the cavity along with the crankcase pressure. The cork breather cover gasket is undamaged and intact (though it is completely compressed at its mating line).

(see image below) I ran the engine for about five minutes and saw a steady drip-drip-drip of fresh clear oil falling from the cooling fin closest to the crankcase. The aluminum engine block is one solid piece all the way to the cylinder head; the cylinder cooling fins are part of the block so there’s no place for oil to escape until you get all the way out to the head gasket – and I don’t see any leaking there.











(see image below) Left and right SIDES of the engine block are clean. All the leaking is occurring at the FRONT, where I can’t see anything, of course…











(see image below) I removed everything from the top of the engine again and found the Blower Housing Baffle (pan) completely clean and dry. Also the top of the breather cover was clean and dry. If the top oil seal (black rubber crankshaft seal) were leaking, I would expect to see oil on these two surfaces and maybe on the underside of the flywheel. *AM I RIGHT?*











(see image below) I opened the Breather Compartment and found only TRACES of oil there. (I failed to clean the oily gunk appearing at the bottom of the pic (front of engine) so I can't tell if that's all old, or old+new). 











The newly cleaned fibrous Filter Element showed a little oil on its bottom surface only, its top and sides were not oily. So there's not a lot of oil passing through the Breather Compartment, right?











The oil could be blowing out under the Breather Cover GASKET... It’s hard to tell, but there MIGHT be shiny oil in the mating surface impressions in the cork gasket… (see image below)











THERE WAS A LOT OF OIL DRIPPING FROM THAT COOLING FIN YESTERDAY. A LOT! SEEMS LIKE WAY TOO MUCH TO BE COMING FROM THE BREATHER COMPARTMENT IF THAT COMPARTMENT ONLY CONTAINS AN OIL MIST. *IS IT POSSIBLE THAT THE CRANKSHAFT'S TOP OIL SEAL REALLY IS LEAKING, EVEN THOUGH IT APPEARS INTACT AND UNDAMAGED?*

*ALSO, MY PAPER PLEATED AIR FILTER IS DRENCHED IN GASOLINE. ANY IDEAS ABOUT WHAT’S CAUSING THAT?* The gasket between carburetor and plastic air filter housing looks damaged, and that’s where the primer squeeze ball is…

Thanks


----------



## 30yearTech (Sep 14, 2006)

Judging from your pictures, the oil does not appear to be coming from anywhere on top of the engine. My best guess is that it may be coming from the sump pan gasket as suggested earlier by geo. Did you check and make sure the breather tube is not pinched behind the air filter cover?

As for the fuel in the air filter, did you happen to tip the mower on it's side with the air filter facing down? Fuel can pour out of the carburetor into the air filter housing if tilted forward or on air filter side far enough.


----------



## ZukiJon (Nov 15, 2006)

I know very little about this motor, but could it be possible that oil is leaking from around the crankshaft? Looked like the bearing had a good bit of oil around it. Just a thought.... I'll be following this thread. I'm curious how it turns out.


----------



## TBm (Feb 10, 2011)

30yearTech said:


> ...the oil does not appear to be coming from anywhere on top of the engine. My best guess is that it may be coming from the sump pan gasket as suggested earlier by geo.


Look at the pics above of the left and right sides of the engine block. They're clean and dry. Would that sump pan gasket be likely to leak only at the front and not at other pointS? The oil dripping from that cooling fin seemed to come from above it. I can't see how the upper and lower engine haves come together relative to that "dripping fin". Can you advise?



30yearTech said:


> Did you check and make sure the breather tube is not pinched behind the air filter cover?


YES




30yearTech said:


> As for the fuel in the air filter, did you happen to tip the mower on it's side with the air filter facing down?


NO

REMEMBER, THE MACHINE WAS RUNNING PROPERLY UNTIL I TURNED IT UPSIDE DOWN AND LEFT IT THAT WAY FOR AN EXTENDED PERIOD SO I COULD WORK ON THE SELF-PROPEL GEAR BOX. SO IT DOESN'T SEEM LIKE A BLOWN GASKET OR SEAL, DOES IT?

*What about WORN PISTON RINGS?* It does NOT appear to be burning (much or any) oil. *If the rings were bad, would I be seeing lots of white smoke? * I was reading about a guy with a similar oil leak, and he was concerned that excess pressure was blowing past the rings and into the crank case...

*Is it still possible that adding RTV gasket sealer to the breather cover's cork gasket might solve this,* based on my latest report/pictures?


----------



## 30yearTech (Sep 14, 2006)

TBm said:


> Look at the pics above of the left and right sides of the engine block. They're clean and dry. Would that sump pan gasket be likely to leak only at the front and not at other pointS? The oil dripping from that cooling fin seemed to come from above it. I can't see how the upper and lower engine haves come together relative to that "dripping fin". Can you advise?


There does not look to me from the pictures, any oil coming from the top of the engine anywhere. That only leaves the crankcase gasket on the oil sump. Yes, it's possible for the gasket to leak at one point, and when they do, they generally leak near the cylinder area. I don't see oil leaks on this model very often, but it's a possibility.



TBm said:


> REMEMBER, THE MACHINE WAS RUNNING PROPERLY UNTIL I TURNED IT UPSIDE DOWN AND LEFT IT THAT WAY FOR AN EXTENDED PERIOD SO I COULD WORK ON THE SELF-PROPEL GEAR BOX. SO IT DOESN'T SEEM LIKE A BLOWN GASKET OR SEAL, DOES IT?


If you stood the machine back up after being upside down, and started it before allowing all the oil in the breather to drain back into the crankcase, excess pressure could build up and force oil out or cause a gasket or seal to fail.



TBm said:


> *What about WORN PISTON RINGS?* It does NOT appear to be burning (much or any) oil. *If the rings were bad, would I be seeing lots of white smoke? * I was reading about a guy with a similar oil leak, and he was concerned that excess pressure was blowing past the rings and into the crank case...


You would see alot of smoke with worn rings, and this is something that happens gradually over time. Since you did not have this issue before turning the mower over, I cannot see how the rings would be the issue.



TBm said:


> *Is it still possible that adding RTV gasket sealer to the breather cover's cork gasket might solve this,* based on my latest report/pictures?


Possibly, but once again, it does not appear to have any oil on top of the engine. You would see oil somewhere on the top of this engine if it were leaking from this area. Sealing the cover if it's not leaking, won't change anything.

I suggest you take the engine off the mower deck and check to make sure all the bolts holding the pan are in place and tight. If you find any missing or loose, then take the pan off and inspect the gasket.


----------



## TBm (Feb 10, 2011)

30yearTech ==

Thanks for the detailed reply. Glad to know it's not likely bad rings. I've been sorta "guessing" at the oil level for years... I see your point about how turning the machine right-side up before the oil drained down from the breather might have increased crankcase pressure to the point of blowing that lower gasket. Gee, I hope not. 

*IS REPLACING THAT SUMP PAN GASKET DIFFICULT?* Specifically 1) do I need any special tools and 2) will things inside remain in place when I split the upper and lower halves? I dread splitting the engine... Is it a simple matter of removing the bolts, removing the bottom, replacing the gasket and buttoning it all up again?


I removed the muffler and did my best to clean all the gunk off the outside of the engine (hard to get in around the cylinder, though). Before I remove the engine entirely as you suggest (or throw in the towel) I'm thinking I could reassemble one more time and run it until it leaks. With the motor clean, I should be able to see where any oil runs down from the top oil seal or the breather cover. _I wish I could put a colorant in the oil so I could track it better._

Beyond that, here are my last two possibilities (grasping at straws ) see image:

A) I found a route (marked in red) for oil leaking from the Breather Cover to make it's way down to the cooling fin where I saw oil dripping. But do you think there's THAT much oil moving through the breather? It was drip-drip-drip-drip, one per second. 

B) The Valve Springs Cover (and gasket). I don't even know if oil flows over the valve springs. If it does, this cover is right in the area where the oil is appearing. *Is it "wet" behind that cover, or dry?*

THANKS


----------



## 30yearTech (Sep 14, 2006)

If you can clean up the engine real good and run it again for a short while, just until the oil appears, you might be able to trace it's origin. There will be oil behind the valve spring cover when the engine is running so it will be wet behind the cover. If the oil is coming from the path of the red dash line in your picture, then it looks like it could be coming from the breather cover on top of the engine, although it does not look wet in the picture. One more thing I failed to answer in my last post, oil will not leak from the head gasket area on this type of engine.

It would be kind of loud, but you might want to try running it without the muffler, you may be able to get a better view of where the oil is coming from. It should not be an issue for the short amount of run time it would take.


----------



## TBm (Feb 10, 2011)

30yearTech said:


> There will be oil behind the valve spring cover when the engine is running so it will be wet behind the cover.


Good. Then that valve spring cover and its gasket are another possible leak point.




30yearTech said:


> If the oil is coming from the path of the red dash line it could be coming from the breather cover on top of the engine, although it does not look wet in the picture.


That's because I cleaned things up before taking that picture.




30yearTech said:


> oil will not leak from the head gasket area on this type of engine.


Glad to know there's at least ONE spot where this thing can't spring a leak! 




30yearTech said:


> It would be kind of loud, but you might want to try running it without the muffler, you may be able to get a better view of where the oil is coming from.


Great minds think alike. I was wondering if I could get away with running it without the muffler while I watch for a leak source. And I'd love to pay my neighbor back for some of the racket he's always making 

Thanks. I'll reassemble and try running it tomorrow. If I do NOT find a leak originating from the engine top (upper seal or breather cover) then I'm going to need your advice on what to expect when removing the bottom half (pan) of the engine. If everything inside WILL remain in place (nothing springloaded flying across the garage, etc) I should be able to handle it.


----------



## TBm (Feb 10, 2011)

I reassembled and ran it several minutes until it leaked oil. It appears the oil is seeping out from *the sump pan gasket line*, up under the cylinder. See pictures below. The oil drips off the very first cooling fin, right in front of that gasket line.











No oil appears on the sidewalls of the breather compartment. But when I pulled the cover off, I do see oil on the top edges of the breather compartment walls, and in the impression lines of the cork gasket. So I'll have to get a new cover+gasket.

No sign of oil atop the upper seal.











I test ran without muffler or air filter. Started it multiple times and it ran like a champ. In fact, it didn't sound any louder without the muffler than it does with it installed... The muffler is about 13 years old. *QUESTION 1: Could a muffler in this condition cause any sort of back pressure that would negatively affect how the engine runs?* 












*QUESTION 2: ASSUMING I'LL BE REPLACING THE SUMP PAN GASKET, CAN TELL WHAT TO DO TO MAKE SURE THE INTERNALS REMAIN IN THEIR PROPER LOCATIONS?* 

I FOUND A BIT OF INFO. SEE NEXT POST.


----------



## TBm (Feb 10, 2011)

I found an old DIY thread from 2003 AT THIS LINK. It discusses (in very little detail) what's involved in replacing the MOUNTING FLANGE GASKET also called the SUMP PAN GASKET. 

Posts #1 and #2 are directly related to my problem. Post #5 by user *rogerh* states the following, _"It was no problem to replace [the gasket] but you need to be sure you don't damage the *governor gear*, and the *oil pump rod* must be in the right place when it is reassembled."_

Any advice on how to accomplish those two?


----------



## TBm (Feb 10, 2011)

*The Sticky at the top of the HobbyTalk 4-Cycle forum contains a broken link for Tecumseh Manuals...*


----------



## usmcgrunt (Sep 16, 2007)

TBm said:


> *The Sticky at the top of the HobbyTalk 4-Cycle forum contains a broken link for Tecumseh Manuals...*


I had the same problem.Try here for Tecumseh manuals.Hope this helps.

http://www.barrettsmallengine.com/parts.html


----------



## TBm (Feb 10, 2011)

USMCgrunt ==

Thanks a lot. I found the VLV manual at the link you provided. That should be a big help. 

My Craftsman 143.986700 engine turns out to be a Tecumseh VLV66-502514C. 

I just put the .pdf VLV manual to good use: 
*The required torque for the flange mount bolts is 100 to 130 INCH-Lbs (not Ft-Lbs).*

Thanks for the link, and THANK YOU for your service as a Marine. :thumbsup:


----------



## TBm (Feb 10, 2011)

I'm going to install a new flange mount gasket (AKA sump pan gasket).

Do I need to apply a gasket sealer, or just lay the gasket on dry?


----------



## 30yearTech (Sep 14, 2006)

TBm said:


> I'm going to install a new flange mount gasket (AKA sump pan gasket).
> 
> Do I need to apply a gasket sealer, or just lay the gasket on dry?



No sealant, just dry. I sent you a PM the other day, did you not get it?


----------



## TBm (Feb 10, 2011)

30yearTech said:


> No sealant, just dry. I sent you a PM the other day, did you not get it?


NO, I didn't see it. Based on your post I just now went to "My Settings" and found that there was no check mark for _"Receive Email Notification of New Private Messages"_. I added a check mark there so I'll see any future PMs. D'oh!

Thanks for offering to send me a .PDF of the manual. I downloaded one for the Tecumseh VLV models in general. Please send me whatever you have, even if it might be the same one. I'm building a collection/library , 

I provided my email address in a PM back to you.
Thanks


----------



## TBm (Feb 10, 2011)

*Gotter Dun!*

THANKS!

I removed the engine from the deck, and in the process removed all the top-end stuff for access to the oil breather compartment (under the flywheel). After removing the bottom-end shaft stuff, I placed what was left upside down on the bench, loosened the seven bolts and carefully lifted the sump pan (mounting flange) off the upper half. 

Post #2 in this thread was by *geogrubb* on 2/20/11. It reads:
*"I think you will find the sump gasket has failed, when it was turned upside down the crankcase breather became blocked, the built up pressure forced a leak at the sump gasket, I think you will find the bolts loose on the sump."*

The gasket was broken in three places. It turned out oil was leaking at the gasket line just below the cylinder cooling fins. The two sump pan bolts below the cylinder were loose, and I found pieces of the gasket laying on the floor of the sump pan right below the gap. See red lines in image below.


Now, I insisted throughout that the oil JUST HAD TO BE leaking from the TOP of the engine. 30yearTech explained how it could be coming from the oil breather cover gasket, and helped me investigate that possibility until he concluded it could not be coming from there. In fact, he reiterated *geogrubb's* advice about how my leaving the mower upside down and then restarting it BEFORE THE OIL COULD DRAIN BACK DOWN INTO THE CRANKCASE probably caused enough pressure to blow the sump gasket. 


I replaced the oil breather cover and gasket. Also replaced the lower oil seal; it was not leaking, but since I had everything apart I replaced it for good measure (the old one came out undamaged, so I'll hold it in reserve in case the upper springs a leak...)

I installed the new sump gasket and got the entire mower reassembled last night (felt like the idiot who took apart his wrist watch ). I filled it with *24*oz of oil (manual calls for 27oz but I'm not taking any chances) and a splash of gas. Wheeled it out, pumped the primer bulb and it started on the 3rd pull. I SEE NO LEAKS and it's running GREAT.

The real test will be my typical 3-hour mow over rough, hilly terrain. Saturday will probably be our maiden voyage. I'll post if any problems appear. 

THANK YOU BOTH FOR THE HELPFUL, KNOWLEDGEABLE GUIDANCE. :thumbsup: 
I could not have accomplished this without your advice.


----------



## geogrubb (Jul 28, 2006)

Success is a wonderful sound. Have a good one. Geo


----------



## TBm (Feb 10, 2011)

Just want to post my results:

I use this machine to mow almost an acre of rough, very hilly land. We're having a weird Spring--unseasonably cold and rainy--so I was not able to mow at the right time. The grass became overly tall, and when I finally did mow (on Easter Sunday because I had to _get while the gettin' was good_) the grass was damp. So my repairs were truly put to the test.

I'm glad to report that the mower ran LIKE NEW, and not a drop of oil appeared outside the engine.

Thanks, guys :thumbsup:


----------



## usmcgrunt (Sep 16, 2007)

Congratulations on a job well done.After this adventure,you can now eliminate your local small engine repairman from your Christmas card list, because you don't need him any more!


----------

