Small Engines (Lawn Mowers, etc.): Oil in exhaust, crankcase breather, piston rings

Question
QUESTION: I recently attempted to repair a tecumseh H70-130123A motor for a john deere snowblower.  I have thoroughly cleaned the carbeurator, changed the spark plug, used new gasoline, changed the oil, etc...  When trying to start for the first time I got the engine to cough and almost start a few times but never was able to get it to run.  I checked that I had spark and the plug was firing.  What I did notice was oil in the exhaust port of the engine and around the muffler.  Any suggestions?

Another Note - I recently replaced the intake valve (the bottom cap holding the spring had cracked - about 1/3 of it was laying in the bottom of the valve housing). I lapped the new valve in and checked the clearance to 0.008 when I was installing.  I also lapped the exhaust valve and checked its' clearance as well to 0.01

ANSWER: Hi Mike,

RE: Tecumseh H70-130123A

Finding oil in the muffler points to either one, (or more), of the

following condition(s):

1.    The Oil is too far past the maximum level recommended  (Manufacturer).

2.   R.P.M. is set too high or Governor is not properly set.

3.   Poss. damage to gaskets, seals - 'O' Rings.

4.   Poss. damage to breather, or breather dirty or not installed

properly.

5.   Piston rings could be not properly installed (seated) or ring

end gaps are aligned

6.  You are operating machine to too severe an angle, cause oil to

spill into muffler (port).

Any or more of the above conditions could be causing one or both of

your symptoms. Start by checking these 6. I would then go from there.

I hope this info helps you out,

Howard B.

---------- FOLLOW-UP ----------

QUESTION: One more question - can I run the machine BRIEFLY (5 minutes) without the breather installed or do I have to buy a new one?  I also have not been able to get the machine to run yet - would a breather problem (or any of these other problems) be enough to prevent machine startup.  Thanks so much for your help.

Answer
Crankcase Breather is a ONE-Way check valve.  

- Breather component - allows air out,

also acts to prevent air coming in.

Also Breather allows the engine to develop a partial vacuum in the crankcase, during the engines' operation.

Any components which might be improperly installed or altered/damaged or missing, result in engine operation not being optimally regular.  

I don't recommend running the engine with the Breather missing, but if  that is what you wish to do then ...  


Regards,

Howard B.