Tecumseh LV195EA (6.5 HP) surging/uneven idle

Pabilo

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I have a Toro Personal Pace mower, model 20017. It has a Tecumseh engine (model: LV195EA, 362003B). I have had it for 15 or 16 years. It has not had a lot of use. It is used only occasionally to mow a small area or trim around beds or trees. Recently, it had become difficult to start and would sometimes miss when I would push down on handle (lifting the front edge up) in a turn. It began to surge as well. I cleaned the jet that holds the bowl in place but it did not help. I replaced the carburetor with an aftermarket brand because it was cheaper than a carb rebuild kit and included extra primer bulbs, a spark plug and an air filter. This carburetor was the correct one for my mower and it got very good reviews. The engine performed exactly the same after replacing the carburetor. The original plug worked fine but it had a little white ash built up on it making me think that the engine might be running lean. Replacing the plug and the air filter had no effect. I checked and reset the governor adjustment with no effect. The two links going to the governor lever are in the proper holes. I cleaned around where the governor shaft exits the block and the whole mechanism moves freely but this did not help. The link that goes to the throttle on the carburetor is in the correct hole. I have checked the fuel line and it is not blocked or leaking. The gas cap is venting properly. It surges even with the gas cap off. I have bent the bracket that holds the governor spring both ways and it increases or decreases the RPM but the surging continues. I can somewhat "tamp down" the surging by screwing the idle adjust screw in until the RPMs just start to pick up but their is still an uneven idle and intermittent surging. The surging begins about 3-5 seconds after the engine starts. This is the case with a cold start (after priming) or after it is warmed up and not primed first. The surging sometimes gets a little bit better after I run the mower for a few minutes, but not always. I took off the new carburetor and checked/cleaned it. I adjusted the float clearance because it was more than 11/64 inch. This made no difference. The intake manifold has no cracks and all the gaskets are good. The head gasket appears good. I have run out of things to try and would appreciate any suggestions on how to fix this. Could the part of the governor that is inside the block be bad?
Thanks,
Paul
 

slomo

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Surging/uneven idle is caused by several things.

Gov could be bad.
Car-bu-trator linkages slash return springs.
Chinese car-bu-trator alert - Get an OEM carb
Spark plug that came with the Chronese carb is probably suspect.
After 16 years a valve clearance check wouldn't hurt.

BTW, is this a fishing experiment? There are a few too many posts like this where the person has checked almost everything possible on a mower. Just look at that paragraph of replaced/checked parts. That mower should run like a top.

slomo
 

Rivets

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Just because an ad tells you that it’s product is a direct replacement, doesn’t make it true. I feel you have been penny wise but pound foolish. I’ve see 75-100 of these symptoms on Tecumseh engines (due to old fuel in the unit) each year and 95% of the time the answer is to properly clean and rebuild the carb. Part number you will probably need is 631021B and costs able $5.00. Take your original carb and follow this is the procedure. I’m will to bet that the engine will run better than with that clone carb.

Needle and seat replacement.
Remove the carb, and then remove the float bowl. Check the float bowl jet (which is the bowl screw) and make sure the jets both horizontal and vertical are clean and open. Tip the carb upside down and remove the float pin and float with needle attached. Look in the float needle passage and you should see the red float seat at the bottom of the passage. This is where a #5 crotchet hook would come in handy as you need to remove this seat. If you have no hook, but compressed air, you can blow through the fuel inlet and try to pop the seat out. Put your thumb over the passage to prevent the seat from flying who knows where. No air or hook try bending a stiff paper clip to dig the seat out.
I would either give the carb a good 24 hour soaking or have it ultrasonically cleaned at this time.
With the seat out clean the passage way with carb cleaner. Now you must find a drill bit slightly smaller than the passage way, to be used to press in the new seat. Apply a very, very small amount of a very light lube to the new seat. 3-1 oil or lighter, to help seat it better. Carefully insert the new seat in the passage way with the rings on the seat down toward the carb body. Slowly and carefully force the seat down with the back end of the drill bit. Once it is seated, check to see that it did not flip and the rings are up. Next check to make sure that the float does not have any liquid in it. If it does, replace. If everything looks correct, attach the new needle to the float and install with the float pin centered. It everything is correct, the float should seat level to the carb body, when looking at it upside down. If everything looks good reattach the float bowl, making sure that both the bowl gasket and the nut gasket seal properly. Reinstall on the engine and test unit. Remember to have patience and take your time. Good luck, but I don't think you'll need it.
PS: On the side of some Tecumseh carbs you will find a plastic cover. Under this cover will be an idle jet. Remove it and check to see that the jet is open both horizontally and vertically. You should be able to push the old float needle wire through the vertical opening.
 

Pabilo

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Rivets, Thank you for your thoughtful, detailed reply. I will rebuild the old one if I can. Aside from the lure of the low cost of the aftermarket carburetor, I was worried about re-using the original one because the nipple where you attach the fuel line was a plastic piece that was pressed (glued?) onto the body of the carburetor and it came loose when I was taking off the fuel line. It is OK to glue it back on? If so, what type of glue would be OK?
Again, thanks!

slomo, I tried the Chinese plug and a new Champion one with no benefit. As far as your question about whether this is a fishing experiment; what is it that I would be fishing for? I took the time to type out a long post so that any reader(s) could see what I had already tried and go on to things I might have missed. I am good at fixing lots of things but I am not a pro at any of them. When I cannot make something work correctly, I want to learn what I missed. If I cannot figure it out, I will take it to a pro to be serviced.
 

Rivets

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I’ve used super glue those nipples with good success.
 

slomo

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Rivets, Thank you for your thoughtful, detailed reply. I will rebuild the old one if I can. Aside from the lure of the low cost of the aftermarket carburetor, I was worried about re-using the original one because the nipple where you attach the fuel line was a plastic piece that was pressed (glued?) onto the body of the carburetor and it came loose when I was taking off the fuel line. It is OK to glue it back on? If so, what type of glue would be OK?
Again, thanks!

slomo, I tried the Chinese plug and a new Champion one with no benefit. As far as your question about whether this is a fishing experiment; what is it that I would be fishing for? I took the time to type out a long post so that any reader(s) could see what I had already tried and go on to things I might have missed. I am good at fixing lots of things but I am not a pro at any of them. When I cannot make something work correctly, I want to learn what I missed. If I cannot figure it out, I will take it to a pro to be serviced.
Was just typing out loud. I've noticed a bunch of posts where guys cover every base and still have a poor running machine. You had an awesome paragraph of details.

slomo
 

Pabilo

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I went ahead and ordered the larger rebuild kit (632760B) because I need to replace the o-rings on the emulsion tube. Also, the Welch plugs are all in bad shape. I have two more questions.
1. If the primer bulb is OK should I still replace it? It is the original one (~2004) but does not have any holes or cracks. It is slightly stiffer than the replacement one that I have on hand (I have a spare bulb and retainer clip).
2. The Welch plugs are quite rusty. Is it worth the effort to remove/replace them to service the small holes/ports below?
Thanks,
Paul
 

Tinker Ty

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Here's a spit in the wind Pabilo... What does your intake gasket look like? I've seen air leaks cause the same issue. You can spray carb and choke cleaner around the carb and if it smooths out, you got an air leak. I mentioned the intake gasket because that's usually the first one that deteriorates first. Just another look at your problem. Good luck. I do agree with the rest of the comments left as well.
 

Rivets

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As long as you have the parts and you are rebuilding the carb, I would replace primer and welch plugs.
 

Pabilo

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Tinker Ty, I replaced the intake gasket when I installed the aftermarket carburetor. I went ahead and tried spraying carb cleaner around the intake gasket and the joint between the intake pipe/manifold and the block. There was no change.

Rivets, Thanks. I will do a complete rebuild when the kit gets here and will update this post after doing that.
 
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