Questionhi, i am having an issue with my lawn tractor. It ran fine the last time we used it, now its sputtering and backfiring when you let the clutch out to a little under half way with or without the blades on. If you hold it in it runs fine. We replaced the spark plugs, cleaned air filter ect. I'm stumped!!!
model # 917.272073
AnswerThere are a lot of things it could be but the first three to check would be airflow, timing and fuel supply. The timing is controlled by the flywheel position and can be checked by verifying that the keyways in the crank and flywheel are aligned. To do this you have to remove the flywheel covers and the retaining nut.
Checking the fuel supply is a bit more difficult but a good indicator would be plug condition. If one or both are very black or gray and ashy, then you have a fuel problem. Also, if this has a twin, verify that both pistons are moving and making power. Broken rods, stuck valves, blown head gaskets, these can all cause power loss. Identifying them may be done with a compression gauge.
Next would be replacement of the air filter. Paper air filters cannot be cleaned. Cleaning them only damages them. Thanks, PK.
