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Curtis B.
Curtis B., Technician
Category: Small Engine
Satisfied Customers: 26057
Experience:  have worked on and around most engine models for 35 yrs./Polaris ATV expert
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I have a model 42A707 that is consistently failing the

Customer Question

I have a model 42A707 that is consistently failing the 590781 coil. When l got the mower it ran fine. As the weather got hot it would run two to two and a half hours and then just quit dead. After letting it cool it would start right up and run again. This continued for a couple of months until finally it wouldn't make spark at all, even cold. I replaced the coil and it started right up and ran about three and a half hours and quit dead. Wouldn't make any spark even with the ground wire removed and jumping from the car to insure good RPMs. I have installed three more coils while trying to figure this one out. Each time it starts right up and runs. Then the coil fails. The longest time one ran was 3 hours the shortest was 27 min. Once it quits there is no spark. You can hold the spark plug wire and feel nothing. Any ideas as to what the problem is?
Submitted: 1 year ago.
Category: Small Engine
Expert:  Curtis B. replied 1 year ago.
Welcome to JUST ANSWER small engines, let me try to help you !! So you get no spark even if you remove the kill wire from the coil? Are you using a Briggs coil or aftermarket? I had the same model and I thought the coil was bad, it would run cold but would quit when hot. Checking for spark I could not see any. I replaced the coil and still had same problem. I found the valves were too tight! After reworking the valves, the engine runs like new and the coil was not problem.
Customer: replied 1 year ago.
Briggs coils. Were the valves sticking? When it stopped running did it just quit dead? No missing or back firing?
Customer: replied 1 year ago.
Also, if it was valves then why no spark when cold?
Expert:  Curtis B. replied 1 year ago.
Mo, valves had zero clearance and engine would run cold, but lost power and would not start hot. And checking for spark, it was not visible. After it cooled, it would start.It may not be your problem, but with nothing else attached to you coil. there is no reason coils should be failing.

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