# Service Manual - Tecumseh TNT100-10079D



## jaygreg

Hi folks! I'm Jay from NE Ohio. I've got an old 21" rear bagger, self propelled Toro model 20775 that's leaking oil. Hasn't been used in years. I've decided to make it a repair project. I've got the parts catalog but not the service manual for the Tecumseh engine. I briefly searched for a library of files hoping to find the manual but turned up empty. Would someone please tell me how I can get a copy here... if that's even possible. Thanks.


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## 30yearTech

You can find links to Tecumseh service manuals in the sticky post thread in the 4-cycle section. The one you would be interested in should be on page 3 and is the service manuals for 3 to 11 L head engines 692509.


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## jaygreg

*Tecumseh TNT100-10079D - shaft component removal*

Thanks for the reference to the service manual. It’s been a big help. I think I found my problem, got some local advice – and a flange gasket – but can’t find specific instructions to remove the “blade retainer” (PN 23-0110) and the “engine pulley” (PN 21-5580) so I can slip the “Mounting flange assembly” (PN 30954B) off the bottom of the camshaft and replace the “Mounting flange gasket” (PN 26750A) that I think is the culprit.

I have the engine removed from cutting blade “housing” (PN 11-0179) and setting on a table. It appears that a wheel puller could be used to remove the blade retainer and pulley but I hesitate to do so until I know what the official procedure is. Can someone point me in the right direction or offer some hints to a shortcut please?


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## 30yearTech

jaygreg said:


> Thanks for the reference to the service manual. It’s been a big help. I think I found my problem, got some local advice – and a flange gasket – but can’t find specific instructions to remove the “blade retainer” (PN 23-0110) and the “engine pulley” (PN 21-5580) so I can slip the “Mounting flange assembly” (PN 30954B) off the bottom of the camshaft and replace the “Mounting flange gasket” (PN 26750A) that I think is the culprit.
> 
> I have the engine removed from cutting blade “housing” (PN 11-0179) and setting on a table. It appears that a wheel puller could be used to remove the blade retainer and pulley but I hesitate to do so until I know what the official procedure is. Can someone point me in the right direction or offer some hints to a shortcut please?


Official??

A wheel puller should work alright for you, personally I use an air hammer. This would not be covered in the engine manual as the engines may be used for several different applications. These parts are installed by the equipment manufacturer and not the engine. A little penetrating lubricant may also be helpful.


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## jaygreg

The wheel puller chipped the engine pulley. Are you sure this is the way this is supposed to be done?


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## 30yearTech

There are many ways that it can be done. A wheel puller can be used, if it's rusted to the shaft, it's possible to damage it when removing. If you damage the adapter, then you will have to replace it!


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## jaygreg

I can't find a part on the parts list for this assembly labeled "adapter". Can you be more descriptive please.


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## 30yearTech

jaygreg said:


> I can't find a part on the parts list for this assembly labeled "adapter". Can you be more descriptive please.


On the Toro IPL the blade adapter is listed as blade retainer ref # 18, this is what I am talking about. It has to come off first, then you will have to remove the self propel drive pulley.


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## jaygreg

The blade retainer was no problem; it's off. I've found another pulley anticipating that this one will be destroyed in the removal process. A local mechanic told me to heat the pulley. So.... guess I'll heat it.


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## 30yearTech

jaygreg said:


> The blade retainer was no problem; it's off. I've found another pulley anticipating that this one will be destroyed in the removal process. A local mechanic told me to heat the pulley. So.... guess I'll heat it.


Usually the pulleys are not that difficult to remove. They are a powder steel type pulley, so they are easy to break. If it's stuck and already broken, a chisel and hammer should do the trick. Just break the pulley along the key way and it should loosen up enough to slide off.


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## jaygreg

I'll give that a try. I was going to buy a coping saw with a metal cutting blade and try sawing along the key. The strokes would be awfully short 'cause there's so little room (I'd hit the "mounting flange" or crankcase with each stoke but...

I'm concerned about the impact all that pounding will have on the oil seal in that crank case base ounce it comes off. According to the manual, there's an "oil sleeve tool" involved in either it's removal or replacement. Can you comment on that please. I don't have the tool. What do I use or am I forced to find someone with the tool?


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## 30yearTech

jaygreg said:


> I'll give that a try. I was going to buy a coping saw with a metal cutting blade and try sawing along the key. The strokes would be awfully short 'cause there's so little room (I'd hit the "mounting flange" or crankcase with each stoke but...
> 
> I'm concerned about the impact all that pounding will have on the oil seal in that crank case base ounce it comes off. According to the manual, there's an "oil sleeve tool" involved in either it's removal or replacement. Can you comment on that please. I don't have the tool. What do I use or am I forced to find someone with the tool?


I have removed hundreds of pulleys and blade adapters with an air hammer and or just a hammer, never had any issues with the seals. You don't have to have a seal protector to install a seal, just makes it a little easier, you can wrap a piece of tape around the crankshaft to protect the seal when reinstalling the sump, if your concerned about any damage.


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## jaygreg

I didn't remove the sump completely 'cause someone told me if I did, I'd have to get involved with timing the engine and that could be tricky. I have no idea if he's right or wrong but it looks like I can replace the gasket without removing that base/flange/sump or whatever we're calling the bottom of the engine that bolts to the mower chasis. Do I need to use some gasket cement? What kind? Both sides?

While I was scraping the old gasket off through the 1 1/2 inch clearance between the sump and the rest of the engine, a metal rod with a ball at the end fell out. From diagram 8 on page 77, it looks like the piston for the "pump barrel". I just put it back after some delicate manuvering and held it in place with a rag 'til I decide whether or not I need to use cement on the gasket.

I haven't moved the gears but 1/2" either way so I assume I haven't knocked anythig out of kilter. The pieces seem to want to slide back together without force so that's a good sign.


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## 30yearTech

You won't do anything to the engine's timing by removing the sump. You would have to remove the camshaft in order to upset the valve timing. You do not need to put any sealer on the gasket.


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## jaygreg

That's good news. I'll give it a try tomorrow. Thanks.


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## jaygreg

Success! Pulley cut off with a Dremel tool and the new gasket is in place. Now my next problem: getting the flywheel off. The service manual calls for a knock-off or knock-out tool in my case. My flywheel doesn't have threads in the three holes at the top to us the flywheel puller shown at the end of the manual nor do I own that special tool. Instructions distinctly state not to use a clamp-type wheel puller and I can see why. Are there any tricks and am I correct in assuming those three holes at the top of the flywheel have to have threads in order for that flywheel puller to work? I may be foreced to put this thing on the back of my friends truck and have him haul it to the repairman who's selling me the parts after all. I really don't want to do that 'cause ... well... it's been fun horsing around with this little project and I'd like the satisfaction of knowing that I did the complete repair when this thing finally does fire up.


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## 30yearTech

Those three holes are for the flywheel puller. The puller Tecumseh uses has self tapping screws that cut the threads the first time it's used. Your flywheel has apparently never been removed with a puller. 

You could haul it to the local repair shop and just have them knock or pull the flywheel for you, so you can continue. Most shops will do it for a minimal fee, especially if you already have all the covers removed and the flywheel exposed.

You could also use a steering wheel puller if you have one, or get the correct knocker for your engine.


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## jaygreg

>>You could also use a steering wheel puller if you have one<< Isn't that the tool with three claws? A friend loaned me a set but I showed him the part in the manual that said NOT to use a claw-type puller.


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## 30yearTech

A puller like this, is what I am referring to:

http://www.tooltopia.com/index.asp?...cse&utm_term=OTC7403&utm_campaign=shopping_r1


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## jaygreg

Is it likely that a puller like that can be rented from Home Depot ... and will have self-tapping screws to cut the threads into the flywheel?


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## 30yearTech

jaygreg said:


> Is it likely that a puller like that can be rented from Home Depot ... and will have self-tapping screws to cut the threads into the flywheel?


I don't know if HD rents any hand tools like this, although you may be able to rent one at a local Auto Parts Store. I am not sure that they would have self tapping screws like the Tecumseh puller or not, but you could tap them out yourself (1/4" - 20 I believe) and then use a regular bolt.


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## jaygreg

A repair shop got the flywheel off for me; $11. Fair deal since I had no alternative. When I openned the little box that contains the points, I found a little piece of felt rubbing the cam. I assumed that was mearly to keep it clean. A friend of mine saw it and suggested I lubricate it. I saw no sound reason for doing so. Who's right?


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## 30yearTech

Your friend.

It's a lubricant wick, it applies a light amount of lubricant to the cam lobe to reduce wear on the points and to help keep corrosion from forming, it also helps keep it clean.


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## jaygreg

What kind of lubricant do I put on it? I already put the flywheel on and torqued it down. Do I really need that wick to be lubricated?


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## 30yearTech

If you already put it back together, then I would not worry about it. If you wanted to put some lube on it, I would use a light weight lubricant such as 3 in 1 oil or WD40.


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## jaygreg

*Compression*

I looked all over that manual and couldn't find any reference to lubricating that wick so I'm gonna' just forget it. I appear to have a bigger problem. I haven't put on the new engine pulley 'cause I wanted to make sure I could get the thing running. If I had to go back into the crankcase, at least I wouldn't have to remove that pulley again. 

Well I replaced the points, condenser, plug, and speced everything out then reassembled... save for the pulley and blade. I did have a small issue with the starter rope rewind assembly when it was removed but I appear to have repaired that. Nothing broke; things just got off-track a tad but when back in place nicely.

Now, however, when I pull on the started rope, I feel very little resistance. I can tell when the piston makes compression but it's very very slight; perhaps the way it might be if the plug weren't in tight enough and was letting air escape. Don't know where to go from here. The style engine is the one with the external coil and, according to the manual, there are no adjustments to make with a gage of any sort short of those I made already when replacing the ignition parts. And I speced out the gap between the coil and magnet (which wouldn't have a bearing on this issue anyway unless the two were rubbing.)

I'm lost for the moment, 30YearTech. Got any suggestions?


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## 30yearTech

jaygreg said:


> I looked all over that manual and couldn't find any reference to lubricating that wick so I'm gonna' just forget it.


I don't know if it's referenced in the manual, that bit of wisdom was picked up at a service update, many many years ago. Like I stated in my previous post, don't worry about it.



jaygreg said:


> Now, however, when I pull on the started rope, I feel very little resistance. I can tell when the piston makes compression but it's very very slight; perhaps the way it might be if the plug weren't in tight enough and was letting air escape.


When you had the sump off, did the camshaft get removed or fall out? 

Did you verify that it was in correctly and the timing marks lined up, before reinstalling the sump?

Have you had the cylinder head off?

The blade acts as a counter balance, so before attempting to start the engine, be sure to install the blade adapter and properly torque the blade on the mower.


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## jaygreg

The only thing that fell out was the "pump barrel" described in frame #13 here. From your reply - since the camshaft wasn't removed - I paid no attention to timing marks; the two halves were never separated but I'm sure the camshaft turned in the process.

The cylinder head has not been removed.

Could the blade make that much difference? I can pull the cord with my left hand from a sitting position; very little resistance.


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## 30yearTech

I don't think the blade not being on it would make it any easier to pull the rope. It sounds like you may have a valve sticking or not seating. You may want to check the valve lash to see if they are within specs.


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## jaygreg

>>valve lash<< ????

I removed the head and found the chamber full of carbon... including a few large pieces. The exhaust valve was caked with with carbon while the intake was fairly clean. Directly under that intake I noticed moisture (gas & oil) that tracked across, not just to, the gasket any on town to the exhaust muffler. I'd been leaking a long time apparently.

I haven't examined the valve stems yet 'cause I need to remove that air cleaner housing to get to the plate that covers those stems. I noticed in the manual there is talk of the end of these stems possibly being worn to the point of needing to replace them. I need to reread that section to see just how I determine if they need replaced.

At this point, do I need to seek someone out - small engine repair shop - who has proper tools to either grind these valves and their seats or possibly be told I need to replace the valves? (Which, I assume, would still mean grinding the seats. Or is that where "lapping" comes into play?)


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## 30yearTech

valve lash = clearance

The valve seats are very hard, so unless there is some damage to them, it's unlikely that they will need to be cut. The valves are quite a bit softer and could have damage, but you would really need to remove them in order to see the seat area good. The exhaust valves on some Tecumseh engines are prone to wear and leaking. If the valves all look good, then you can probably just set the clearances and lap them and be alright. Even if you need to replace one or both of the valves, if the seats are not damaged, then lapping would be sufficient.


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## jaygreg

>>set the clearances<<
I'll have to look this up again later this evening. Don't recall anything about adjustments I can make relative to valve clearances... short of grinding the faces. But I'm sure it's there, 30YT.

But yet ANOTHER issue cropped up, the piston cylinder. The shop I've bought my parts from, whose owner has steered me as you have, ran his thumbnail inside the top of the cylinder, turned to me and said... "You're done." He felt a grove has been cut into the wall too sever to make repair practical. A friend who was with me did the same but on the way home said he felt it could be honed to accept an oversize piston and rings. The own didn't speak of a hone; only turning it in a machine shop which is why he felt the cost would be prohibitive.

But I have a close friend who owns a tire mold shop; lots of cutting tools, boring mills, turning lathes, etc. If he has machine time to spare, I'm probably home free. But I'm curious about my friends comment. Could he be right that the job could be done with a hone? Is that enough precision?

Keep in mind that this project is education for me; time I have, and I'm willing to pay a reasonable amount to repair this thing provided the chance of success is significantly in my favor. If I have to tear the whole thing down... so be it. I'm game. But if I have to pay a $100 to bore the cylinder and $50 to have the valves faced on a precision machine... well... I may think twice. 

What's your take on the hone. 30YT?


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## 30yearTech

Well if you are so inclined and have the time, then it may be worth looking into. From a stand point of cost to have the work done, I am with the shop. It's just not cost effective, I could not do the work for one of my customers and have them come out ahead. It would just be too costly to do.

Most small engines are cleaned up with a cylinder hone, although not the same type of hone that is used just to deglaze the cylinder. Before you decide to go to an oversize piston and rings, you need to find out if they are still even available. Tecumseh closed down last year, and some parts are no longer available. As for the valves, they are adjusted by grinding a little off the valve stem to set the proper clearances. Once again, you would have to remove the valves and inspect the valve face and the seats for damage that may require more work then simple lapping.


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## jaygreg

>>Most small engines are cleaned up with a cylinder hone, although not the same type of hone that is used just to deglaze the cylinder.<<

"Cleaned up" and no "deglazed"? This means I could remove that grove successfully with a hone rather than have it bored out on a boring machine?

I was told by the shop owner that I'll find the specs for all oversized pistons for this engine in the manual. I'll check in the AM.

I assume the manual will also tell me how to measure those valves?

I have another Toro that I think is the same model but electric start that I bought new but sorted it when I got as a gift the one I'm attempting to work on, Tomorow I plan to pull it down from storage, remove the head, and examine the cylinder to see if it's better than the one I've been planning to repair. It hasn't been started for 30 years!


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