Hi,

I recently got a craftsman snowblower with a tecumseh 5 HP engine. I cleaned the carb and got her running fine yesterday. Today I decided that I would clean the head and the valves, so after shining up everything the snowblower ran very poorly. I think the muffler might need a new gasket because I know that it is slightly ripped. Also I was wondering if some the carbon from scraping the piston could have made its way back into the carb. Is that possible. I also used a generous amount of grease lightening to clean the head. Could the grease lightening cause problems by getting into the valves and down past the piston? The engine is just running very rough and will not idle without dying.

What do you think the problem is and what do you recommend I do? Thanks in advance for any help. Bob

Did you scrape the head gasket seat at all? If you scraped on it hard enough it may be leaking causing low compression.

The muffler gasket shouldn't cause anything as far as I know.

Using any sort of household cleaner is not a good idea. Use diesel fuel, sea foam, carburetor clean, or just gas to clean the engine.

no I didn't scrape the head gasket seat. Is it possible for any small debris that got under the piston or the valves to get into the carb?

I retightened the head bolts an 1/8th turn made sure they were all tight. I found out that I never tightened the spark plug. Now the engine runs well but it cuts out after running for about 10 to 20 seconds. I quickly pulled the bowl nut and drained the bowl it looked dirty with some sediment. I cleaned the main jet. And it runs nicely for about 10-20 seconds, but then just seems to starve for fuel. I am thinking i need to pull the carb and get the rest of the sediment out? What do you think?

Sounds like a plan, taking the carb off again and cleaning it again wouldn't hurt.

Before I took the carb off, I decided that I would see how it ran (now it is a day later) the engine was only running on 1/2 choke and searching.
I took the carb off and it did not look too dirty at all, but I went through it all with carb cleaner one more time. I noticed that the gasket on the bowl was looking a little bit rough. In fact, it had a ridge worn around the middle of it. I knew that it did not look like the bowl gasket from my other tecumseh snowblower, but I figured that this carb was a different design and it requires this "different" looking bowl gasket. When I tried to put the old bowl gasket on it looked stretched out and I did not want to use it. I had another bowl gasket that I put on even though it did not have the ridge. It seemed to go together pretty well. I installed it on the snowblower and it ran at just about 100%. I didn't want to get the neighbors mad so I turned it off after about 3 minutes of running without the choke on. I am figuring the the original bowl gasket was just the standard tecumseh flat circular gasket, but was really worn out. I believe that my problems last night were due to water in the carb. And the problems today were that due to the poor bowl gasket the carb was either sucking air (I should have sprayed starter fluid on the carb when it was running to see if it surged), or the main jet nut on the bottom of the bowl was positioned up too far because the bowl gasket was shot, and fuel was not being delivered properly. The moral of the story, always replace all the gasket when rebuilding a carb, and if you run out of wd-40 for cleaning the head don't use a water-based product such as grease lightening. Thanks for the help and I am learning a lot from this forum. Do you think I am right about my diagnosis?
Bob

WD-40? that isn't a good cleaner either and leaves a residue after it dries, you don't want a residue left over

like said about, use of of those products or even ether

One thing I do remember from SE school was ALWAYS use new gaskets on all engine parts if you take it apart,and oil seal too. There is nothing worse than having to take an engine apart again because some old gasket or oil seal is not doing it's job.