# Tecumseh LV cutting out / running rough / hard to start



## sfontain (Aug 8, 2009)

Hi all, first post here. I have a 3-year-old Toro walk-behind mower with a Tecumseh 6.5HP LV195EA. I have always run the mower dry for winter storage, changed the oil every spring.

Symptoms began early this season, with the mower occasionally missing (I think), much as if it were running out of gas. I mow about every week to two weeks, and maybe over 3 mowings, the engine died out on me in the middle of mowing about once per mowing, and became harder and harder to start. I took off the carb bowl and let it drain out and that *appeared* to fix it for long enough to finish mowing; it started right up and ran like new for the rest of that particular mowing.

Since then, the mower became unable to start at all. I tried draining the bowl again (I later discovered I had not replaced the bowl properly: the gasket had expanded from being soaked in gas, and the float pin was sticking out enough to obstruct the bowl from being seated properly, but I've since resolved this). I tried draining the bowl once again, no luck. Then I squeezed the main fuel line and it started right up (no idea if this was random luck or what).

Finally, I've taken off the carb and intake manifold and shot carb cleaner all over them. I checked the bowl nut and nozzle for debris and there was really nothing there. The O-ring on the top of the nozzle doesn't look pristine but I don't know how bad it has to be to replace. When putting it back together I bent the governor lever (where the carb throttle connects) to get my linkage reinstalled. (I now know this is not required,but it seems otherwise impossible to reattach the spring and the carb throttle without actually removing the carb. I believe I bent it back afterward to its original position, but I'm letting you know about this in case it's a clue.

Well, finally, I've changed the spark plug and got it running again, but it now constantly runs rough (and I've only run it at idle--no mowing). I can see visible spark on each crank when I take out the plug and ground it to the engine. At first, I was running it and I could see the carb throttle constantly moving back and forth. Maybe it was just cleaning out all the crap I sprayed in there. This problem has since resolved somewhat, but even though the throttle isn't going crazy, the engine is still missing every couple seconds.

Well, I thought, rough is better than nothing, so I was going to just mow with it soon. But last night I moved the mower and I saw gas leaking out again after sitting all day. I found out it was leaking from the plastic piece that sits between the air filter housing the the carb (it's screwed onto the carb). I took that off and ensured the gasket was good; it looks like the carb was just full of gas and it ran out when I moved the mower. (Is this normal?)

However, the air filter *may* have been soaked with gas because of this. All my rough running had occurred with the air filter off. So I put the air filter back on just for the hell of it and pulled the cord, and the engine veerrrry slowly wound up (spit some black smoke out the muffler) and then started to run *great* with the air filter on. Now it's bobbling a little bit still, but if the engine is running so much better with the air filter on (which may have had gas in it), I suspect that's a hint, too.

Sorry for the long post, but I've been messing with this for a while and I had a lot of diagnostic info to explain.

Thank you!


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## 30yearTech (Sep 14, 2006)

Sounds as if your carburetor may be flooding. Could be a bad inlet needle and seat, or a bad float. Too much fuel and the engine will run rough. The O-Rings on the nozzle (there are 2) are usually good for 3-4 seasons and will usually need replacing, if in doubt, then replace them.


Another thing to check for is a sheared flywheel key, this can make an engine run rough also.


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## sfontain (Aug 8, 2009)

I am inclined to agree that the carb is flooding. I'm just surprised as the carb appeared to be pretty clean and is only ~3 years old. The needle stops the fuel flow when I hold the float up by hand, though of course I have no way to know if it's actually floating when the bowl is in place and there's fuel in there. It does seem as though the fuel level is getting too high, and perhaps I damaged something when I took the bowl off the first time. 

Does the nozzle have to come off the nut to get at the o-ring closest to the nut? If so, how do I get it apart?

Thanks!


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## 30yearTech (Sep 14, 2006)

The nozzle is plastic and comes out the bottom of the carburetor. 

http://www.imower.com/KMtec_carb.htm

Try pushing with a flat blade screw driver on the nozzle through the throat of the carburetor to remove it. I use a paper clip with a little hook bent on one end to extract them. Be careful or you can damage the nozzle.


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## sfontain (Aug 8, 2009)

Ahhh, okay, that diagram helps a lot. So, I haven't actually had the nozzle out. What I believe is an o-ring is sitting inside the opening of the nut. I couldn't decide if it was a gasket or crud. It definitely doesn't look like those nice new o-rings in the picture.


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## sfontain (Aug 8, 2009)

Okay, long time no post.

It still runs rough. Tonight I picked up a carb repair kit with screws and gaskets and such. I replaced the O-rings on the plastic nozzle, and you were right--they were shot. The top one disintegrated in my hand when I smooshed it, and the bottom one wasn't far behind. I also did the bowl-to-carb O-ring but it wasn't terrible.

The repair kit also came with a needle and seat. I guess my next course of action is to replace that. Is this just a matter of pulling out the old seat and pushing in the new one or is it any more complicated than that?

Thanks!


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## hd4ou (Aug 25, 2009)

Its not really all that complicated. take that same paper clip and pull the old seat out or use a pic tool with a slightly bent tip to get it out. Take a good look at your new seat and you will notice 1 side has some rings or grooves on it. That side is the one that goes into the hole. this is very important. make sure those grooves go in first. use a little oil on the seat to make it slide in easier. Now take a flat nose punch and push the seat in all the way. make sure its seated all the way to the bottom. Now replace needle just like the old one came out. the open end of clip should be pointing towards the choke. once the float is installed flip the carb upside down and see that the float is parallel with the carb body. If its way off then recheck the seat and make sure its seated. if its close you can adjust the tab that the needle clip is on accordingly.


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## sfontain (Aug 8, 2009)

Well, thought I would give you the update. After cleaning/replacing many carburetor parts and the spark plug, I just replaced the inlet needle, clip, and seat, and ran the mower for about 15 seconds and it seems great. So I'm guessing either the seat was bad or it was clogged up a chunk of fuel hose. If this happens again I will probably replace the hose.

Thanks all for your help! After many weeks it seems to be fixed!


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## hd4ou (Aug 25, 2009)

might as well change that little bit of fuel line anyway. after so long those fuel line will start to deteriorate and even the tiniest bit will cause grief as you have experienced. something got into your needle and seat area to cause your problem to begin with weather it was dirt or a piece of old fuel line. flush the tank, replace fuel line, use new clean gas with a bit of seafoam in it. Should fix you up for quite a while. glad you got it running by the way.:thumbsup:


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## sfontain (Aug 8, 2009)

Okay I'm reviving this thread. Here's my current situation.

The mower sat all winter, I just dug it out. I replaced that small piece of fuel line so no problem there, put in fresh fuel, and sure as hell I started the mower and it's rough again and/or stalling.

I took the carb apart again and sprayed carb cleaner all through it--up the the weekend and found what looked like a tiny piece of red plastic not the size of a pinhead inside the carb bowl--a piece of either the plastic nozzle or a piece of primer bulb. I took this out and put in some fuel and got the mower started and running flawlessly--I assumed that the red plastic was clogging something and it was fixed, and I was amazed.

Of course I was wrong. Within 12-24 hours, I smelled gasoline in my garage and found it was dripping out of the carb at the air intake(where the air filter attaches onto the carb). I think the carb bowl is very slowly flooding while the mower is parked and filling up high enough so that gas comes out the back of the carb via the air intake. It's leaking just enough to make it drip a couple of times a minute, so it takes 2 days to empty out a cup of gas onto my mower deck and make the whole area reek.

But I'm confused. Last fall I installed one of those sort of "carb reconditioning" kits with the bowl o-ring, fuel inlet seat, needle valve, and the little wire that hooks the needle valve to the float. That "fixed" it for a few mowings but then the problem came back. I did take out the valve seat when I sprayed carb cleaner but it does appear that it's seated just fine--unless maybe I damaged when I pulled it out, maybe...?

I also put the float in a bowl of water and it floats just fine. I don't hear any sloshing in the float either. The float sits perfectly level when I hold the carb upside down, too.

At this point I'm about ready to get a $50 Oregon carb off of eBay. The stupid parts kit costs $15-$20 as it is so it's almost not worth another one. Is there anything that would explain fuel very slowly leaking out the air intake while not running, besides the bowl flooding because of a bad needle valve seal? I haven't pulled out the plastic nozzle but even if that's broken, that shouldn't cause the bowl to flood while the mower is parked, should it?

I have one other question: On this carb there is a fuel intake hose but there's also another black hose with a white dot that attaches to the top of the carb, and the other end disappears into the engine. What is this hose and what is its function?


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## 30yearTech (Sep 14, 2006)

sfontain said:


> I haven't pulled out the plastic nozzle but even if that's broken, that shouldn't cause the bowl to flood while the mower is parked, should it?
> 
> I have one other question: On this carb there is a fuel intake hose but there's also another black hose with a white dot that attaches to the top of the carb, and the other end disappears into the engine. What is this hose and what is its function?


No, if the nozzle is broken, it should not cause the carburetor to flood, unless it's somehow trapped in the float and keeping it from working.

The hose that attaches to the top of the carburetor is the oil breather hose from the crankcase, this just vents the crankcase and any oil that may vent out, is fed into the carburetor to be burned with the fuel.


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