# 10.5HP Tecumseh Advice?



## super_coo (Jan 8, 2014)

Hi new guy here looking for advice,

I have a Yardworks snowblower with a 10.5HP engine (LH358SA) that's been running rough the last few times I've used it. It idles rough and the exhaust makes popping noises all the time no matter where I have the throttle. I also noticed the last time that there is a lot of air blowing out the front of the engine near the cooling fins blowing towards the front of the machine. That doesn't seem normal to me anyway, I would have though only air should be coming out the exhaust. It seems to run smooth when it's throwing snow under load though. It also seems louder than normal...

I've taken apart the carburetor and it was really clean and the little jet holes were all ok as per the youtube videos I watched. I've also installed a new RJ19LM spark plug as well as changed the oil.

It seemed to start when I got 10l of fresh fuel and added 30ml of stabilizer to it. That is probably just a coincidence though.


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## td5771 (Feb 21, 2011)

The air blowing out the fins is normal as it is an air cooled motor. The flywheel is also a fan and pulls air in from around the pull start and pushes it through the fins to cool the motor.

Do you have an adjustable carb or a preset one? Does the fuel bowl nut have a small screw in the center of it or is it flat?

If its adjustable we can adjust it more, but if its flat you can either drill out the jets to make the mix richer or swap to an adjustable carb.

If it is a non adjustable fixed jet carb see if it gets better if you close the choke a little. That will restrict the air and in essence make the air fuel ratio richer.


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## super_coo (Jan 8, 2014)

Hi thanks for the response.

This one has the fixed jet carburetor so there are no adjustments. Like I said I've taken it all apart, it was very clean and I can at least say that the tiny holes that sometimes clog up were not clogged up and I could pass small wires through all of them. That's not to say there's not something else wrong with the carburetor though...

I've tried different settings with the choke and it does not seem to help.


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## td5771 (Feb 21, 2011)

I put a link below, when you rebuilt the carb did you remove #36 in the diagram, its the emulsion tube and has 2 very small o-rings on it as well as very small holes on the sides to meter fuel. 

what about the welch plugs? The one under the float doesnt really have anything under it but the one on the side of the carb has tiny holes (much smaller than the ones in the bowl fixed jet) under it that need to be clean.

Parts and Diagrams for Tecumseh TEC-640054


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## Grunt (Nov 11, 2013)

Here is a link to carb cleaning in case you don't have the information.

Disassembly, Cleaning and Repair of Tecumseh Series 1 Emission Carb 640084B

The popping through the exhaust could be caused by the valve not closing completely. Have you checked valve clearances yet? I just worked on a Tecumseh 5 hp that needed .007 removed from the exhaust valve stem before the valve seated and had the required .005 clearance. Here is a link to the service manual also. Hope this helps.

http://www.barrettsmallengine.com/manual/tecumsehlheadmanual.pdf


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## ranvette (Jan 5, 2014)

I would get a Oregon adjustable carb if there is one available.I went threw takeing the carb apart several times on my ariens st824 Tec 8 hp.Never could see anything wrong at all with it.It was also miss fireing every now and than.I put a new oregon replacement carb and it runs just perfect now.There only around 55 bucks to.Plus you can get rebuild kits for them to cheap when needed


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## super_coo (Jan 8, 2014)

Hi guys I just wanted to update that I gave up. I checked everything I could and I couldn't figure it out. I ended up taking it to a local reputable small engine shop and they replaced the carburetor after soaking it did not help. I also installed the Clarence Impeller Kit this past weekend and they are calling for 25cm snow tomorrow so I'm really excited to test it out!


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## Kiss4aFrog (Nov 3, 2013)

Let us know how you like the kit.


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## HCBPH (Mar 8, 2011)

*Carbs*

I've also replaced more than one problematic carb with an Oregon for the correct size engine with adjustable jets. Biggest thing is insure you get the right throttle linkage along with carb. It's saved me alot of headaches when I can't get the original carb to work right.


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