QuestionI have a 1969 Tecumseh LAV 30 lawn mower. The engine was running quite poorly and the governor shaft was bent on the inside of the engine so I decided to perform a complete rebuild. I took the engine completely apart, to its last bolt and washer and cleaned and measured every single component. All the parts checked out great, the cylinder wall looks nice but the hone marks are pretty much gone. I repaired the governor and then renewed all the gaskets and put it back together. I rebuilt the carb, new diaphragm and new seals etc. I was certain the engine would run great but it does not, here are the symptoms after pushing the prime bulb 7 times.
1) starts but runs rough and then dies
2) after re-start it hickups and sometimes backfires with white vapour coming out of the air filter housing.
3) Eventually dies or continues to sputter and hunt for idle.
I started with the mixture and base idle screws 1 1/2 turns out and I try to adjust them as the engine is stumbling but it is no use.
The only thing I did not service (or even check) was the ignition system. It is original. Is there a chance the spark is too weak or unpredictable to fire the fuel? But why would this cause backfiring ?
Also, I screwed a carb from a TVS100 onto my machine and it still did not run properly.
Any hints?
Thanks,
jeff
AnswerHey Jeff,
If the engine is a 1969 Tecumseh i would suggest getting a new ignition system and spark plug because you may be getting a spark but just enough to ignite the gasoline and run the engine poorly.The reason for white mist is most likely unused gasoline from the piston chamber. Hope this helps. Good Luck
