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Curtis B.
Curtis B., Technician
Category: Small Engine
Satisfied Customers: 26039
Experience:  have worked on and around most engine models for 35 yrs./Polaris ATV expert
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My lawnmower backfires and it would not start. WHY! I see

Customer Question

My lawnmower backfires and it would not start. WHY!
JA: Do you have fuel in the tank? If so, is the shut-off valve open and the fuel clean?
Customer: I see fuel coming out the carb going the wrong way
JA: Do you plan on doing the work yourself?
Customer: If I can
JA: Anything else we should know to help you best?
Customer: I start the engine normal and as I was cutting the gras the eengine started to work as if the choke was on then died
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Small Engine Technician about your situation and then connect you two.
Submitted: 5 months ago.
Category: Small Engine
Expert:  Curtis B. replied 5 months ago.

Remove the spark plug and hold finger with rag over the spark plug hole while you crank. It should have enough compression to move your finger. If compression is low, you likely have a stuck valve, which lets it backfire through the intake, as the spark occurs with valve not fully closed. Make and model of the engine?