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I changed the fuel from last season and the disassembled the carburetor and it looks clean. I can now get the lawnmower to start by priming it with fuel, but then it runs erratically for 30 or 40 seconds and then shuts off. Not sure what to do. Model 16575 made in 1987.
Answer -
First, try loosening the fuel cap and see if the problem persists. If this corrects it, there is an issue with the tank vent in the fuel cap. It will need to be cleaned out or the cap replaced. If this has no effect, it is likely the carb has a passage that is still blocked, especially since fuel was left in it. It is critical that you use a piece of tag wire to push through all of the internal passages to get it clean. Some of these passages are small and difficult to see so you will have to be diligent. Hope this helps.
All passages are clean. Obviously from this incident I am going to learn a lot about lawnmowers. The problem is related to the flap inside the carburetor; it never opens unless I push on the lever on top of the carburetor that is spring loaded. That lever has a piece of hooked hard wire going to the "governor". There is also another spring loaded wire that goes to the governor, but that looks to be hooked up right. The lever on top of the carburetor has three holes in it, and I have tried them all, and the lawnmower will not run unless I physically hold in the lever myself. There is something either not hooked up right or out of adjustment, because the governor should be pulling that lever so that the carburetor flap is open. I could send you the parts layout, but this web site looks like it only accepts text. What can you tell me about this from what I have described that would help me repair this?
Mike
AnswerIf you are telling me there is no issue with the fuel system, it's possible the issue is related to compression (burnt valve or excessive tappet clearance) that affects the engine once it warms up a bit. If compression is the issue, you should hear a whisping noise through the exhaust when you try to start it after it has quit. Otherwise, the trouble could be related to the ignition module becoming inoperative once it gets warmed up. If this is the problem, you need to check for spark immediately after it quits. Hope this helps.
