QuestionMower fires initially when cold but runs at slow speed at full throttle/start position. After warming, there's a burst of speed but immediately dies. I can restrict air-flow at the horn with my hand to keep it running but with the air filter on, it dies. Before this problem, the mower only ran at high speed - either fast or off from the throttle control.
I have cleaned the carb and passageways; replaced the diaphragm and plug; checked the throttle/governor vane/spring linkages v. manual. Throttle jet is set to 1-1/2 turns from seat to start. Idle adjust on throttle plate never bottoms due to vane linkage. What gives? Can/should the governor vane or idle plate be adjusted so the idle adj screw bottoms? What's out of adjustment?
Thanks for your help.
AnswerNo adjustments on the governor vane. Many times on the older mowers the aluminum carburetor warps causing and air leak, running lean. By placing your hand over the horn you restrict air which richens the fuel mixture allowing the engine to run.
I would check the intake tube and gasket for leaks. This will also cause a lean condition. As for the carburetor, you can use a stationary high speed sander to "true" the warped carburetor bottom. You can also do this by hand with a file. Of course you will have to remove the carb tube(s) to sand or file...the tube can be difficult to remove. Once the carburetor base is "true" the engine should run fine.
You other option is just to replace the entire carb/tank assembley. This option is more expensive, but much quicker and easier.
Let me know if you have any other questions.
Eric
