QuestionQUESTION: Hi
I have an older Craftsman 8hp Tecumseh Snowblower with adjustable carb. I have put a new carb kit in it cleaned it twice, replaced fuel line with a new one,cleaned fuel tank,new gaskets for intake. The muffler glows red on the bottom which I believe means it is running to lean..I have tried all these measures but I can't stop it from surging.Do you have any suggestions how to repair this? Thanks Mike
ANSWER: Check the head bolt torque. Do you thing someone replaced the carb at some point in time to a too small of carb?
Have you checked the valve clearance and inspected the valve to make sure one of them is not leaking? You will need a leakdown tester to check to see if a valve is leaking. You other option is to remove the head and inspect the valves but then you will have to replace the head gasket and you might as well lap the valves since you have the head off.
I'd start by checking the head bolt torque first as I have had some head bolts loosen on Tecumseh engines and cause lean running conditions.
Eric
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QUESTION: That was quick.....I don't think the carb was changed. I will check the head bolts,what torque should they be? I have a compression tester that I bought awhile back .....How do I use it? I will check the valves and will get tool to check clearance Thanks Mike
ANSWER: Most likely the head bolt torque is 200 inch pounds. I need the engine model number to verify.
The URL below should take you to one of the Tecumseh engine repair manuals that has the specs.
http://www.smallenginesuppliers.com/html/engine-specs/tecumseh/Tecumseh_L-Head_E
You can find the Tecumseh service manuals online if the one above is not correct.
A compression tester will not usually tell you if a valve is leaking or the head gasket is leaking...unless they are leaking really, really bad...and then I can usually feel something is wrong just by pulling the starter cord.
Check You Tube for leakdown testers. This tool is much more accurate at determining if any internal engine parts are leaking.
What is the engine model number?
Eric
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QUESTION: I just tightened the head bolts a couple were able to be tightened......I started it and muffler turned red again and surging I don't know the model of engine as there is no label......I can get model of snowblower though its frustrating its a good snowblower and I don't want to scrap its a good blower......I will try the other methods Mike
AnswerWhat model numbers do you have?
Most Tecumseh engine will be a model HSK-xx. If you look at the service many of the valve specs are .008 of an inch...very common.
I'd pull the valve cover off as it is easy to do and check the valve clearance. You can set the piston at top-dead-center on the compression stroke just use a drinking straw inserted through the spark plug hole. Only takes a few minutes and you will rule out valve issues, for the most part, just by checking the clearance.
Send me what ever model number(s) you have.
Eric
