I have a Techumseh 5 hp Snow King. Long story short it ran great, now it wont run under load. Tear down and inspection has revealed that the exhaust valve is opening partially. I removed the Cam and it has a second "bump" on the exhaust lobe 180 degrees out of the normal lobe. Is this normal? It is causing the exhaust valve to "dance" and I believe it has worn out the valve guide. Any fix for the valve guide would be appreciated. I don't want to put oversized valves in it. Tech rep said the valve guides were considered a non-serviceable item.

v/r
Jixxer

 

Please post model number and DOM. There are many engine differences between L-heads and OHV’s and even between years manufactured.

In the meantime you can download a servive manual for the engine at this link:
http://toprake.com/index.php?module=...position=11:11

 

After thinking about the “second bump” and valve not fully opening I believe you probably have a worn cam. The “second bump” was probably created by metal surface loss.

 

Model # LH195SA (engine)
Spec 67419V
Serial # 47.88700.1 (snow thrower)
It is 3 yrs old

The valve opens normally on the lobe. The problem is when it gets 180 around the valve raises and jiggles. I considered metal wear at first. But the fact that it raises the exhaust valve and kind of jiggles it makes me think different. Intake valve cam is smooth and round 180 degrees out. The exhaust valve cam 180 out is a distinct raised point. I have checked for end play of the cam into the block and there is nothing out of the ordinary. I wish I could physically show you this cam. I'm not sure if a picture would help. Can you attach pictures on this site? Any help is appreciated, I have exhausted all my means

 

After reading the service manuel, the bump is normal. It is called a BCR. (Bump Compression Release). I have never heard of such a thing. The problem must be in the valve guide not letting the valve seat properly. Thanks for the link to the service manuel. Any ideas on replacing the valve guides?

v/r
Jixxer

 

The bump is on the intake cam, the cam closest to the gear.

Is it actually the intake valve you have a problem with?

The valve dance you mention sounds like it may be valve guide wear.

 

All of the problems are with the exhaust valve. The "bump" is on the exhaust lobe. When you turn the engine over, during the exhaust cycle, the valve goes straight up and down. When the cam comes around to the "BCR" the valve moves back and forth as it raises and lowers. I suspect valve guide wear. Any sugestions on how to fix the problem without going to oversized valves?

V/R
Jixxer

 

Tecumseh has used a variety of compression release systems and yes, BCR is one of them. For some reason I was fixated on a mechanical release for your engine. The cam 33158 in your engine is a BCR cam.

Oversize valves can only be used if the valve guides are not over the limits of the oversize valves. For Tecumseh oversize valves are the only option.

I suspect if you pull the valve, you will see an egg shaped valve guide. This is common on Tecumseh engines used in heavy load applications, e.g. tillers, snow throwers.

I have seen this engine online for around $160.00 plus shipping. By the time, you purchase tools and parts it may be cheaper to replace the engine.

If there is enough wall thickness (material) around the guide, you could have a machine shop ream it and make guide bushings of standard size. I did this for a customer who had a sentimental attachment to the engine. He could have bought a new engine cheaper.

 

Thanks for the advice. Here is where I am at right now. I pressed the old valve guide out. It is worn out. For the life of me I don't understand why Techumseh has labled the removeable valve guide as a non-servicable part. I've got a friend that has access to a machine shop making a new guide to press in. Any idea what the tolerance should be for the valve in the new guide? Incase this fails also, can you tell me the best place/price for a replacement engine? I started looking for one but, I'd rather hear it from someone that the place is reputable.

Thanks again,
Jixxer

 

Can you give me any advice on a reputable place to get a replacement engine?

 

I have purchase engines from:
Small Engine Distributors
Small Engine Suppliers
Small Engine Warehouse and
Tulsa Engine Warehouse

I have never had any issues with any of them personally.
Just be sure to check their terms before making any purchase.

Best of Luck...