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Curtis B.
Curtis B., Technician
Category: Small Engine
Satisfied Customers: 12892
Experience:  have worked on and around most engine models for 35 yrs./Polaris ATV expert
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10.5 horse week to no spark. New ignition mod, checked

Customer Question

10.5 horse week to no spark. New ignition mod, checked keyway. isolated stop switch. Spark gets weaker with each rotation?
Submitted: 9 months ago.
Category: Small Engine
Expert:  JohnF2015 replied 9 months ago.

Hi, my name is***** will be assisting you.

What did you set the gap at on the ignition coil when it was replaced?

Is this an electric start?

Customer: replied 9 months ago.
I set it with the card supplied by briggs. no it is not electric start.but I am using a drill to turn it over
Expert:  JohnF2015 replied 9 months ago.

So it is firing all the time but just seems to get weaker the more that you turn it.

I am to think that it could be due to the compression release not working properly so that the engine does not crank over as easy as it should. The first thing that I would check is the valve adjustments, make certain that both valves are set at .004 inches when the engine is cold. If the adjustments become to far out it can cause the engine to crank slowly which will cause poor spark since the flywheel isn't passing the ignition coil properly to provide a good spark.

Customer: replied 9 months ago.
it is turning over quick enough because I have the spay plug removed. in four rotations there is no spark.
Expert:  JohnF2015 replied 9 months ago.

What happens if you remove the small ground wire from the ignition coil that plugs onto it? Does it change the performance of the ignition coil, will if fire longer?

Customer: replied 9 months ago.
no that was the first thing I tried
Expert:  JohnF2015 replied 9 months ago.

If it still stops firing with the small ground wire unplugged from the ignition coil then it has to be a bad coil. I would at that point return it to place of purchase for a replacement, just let them know what it is doing and they should replace it to you at no charge.

Customer: replied 9 months ago.
that I did . this is the 2nd one
Customer: replied 9 months ago.
any ideas?
Expert:  JohnF2015 replied 9 months ago.

Only other thing would be if you are mounting the ignition coil upside down it would cause you problems. Make certain that the ground terminal is toward the block not pointing out toward the blower housing.

Customer: replied 9 months ago.
sir I have it mounted correctly. could it be a weak magnet on the flywheel
Expert:  JohnF2015 replied 9 months ago.

Will the magnet hold a medium sized screwdriver to it without any problems? If so then it is not likely the magnet. It would be odd for the magnet to work sometimes and not others.

Customer: replied 9 months ago.
it seams to I amjust at a loss at this point
Expert:  JohnF2015 replied 9 months ago.

If you are getting a spark for a moment and then it goes away this tells me that the ignition coil is bad or going open after only firing a few times. It is odd that you would have two back to back that would do the same thing however it is not impossible. Briggs did change the manufacturer that is making the coils for them and I have seen some issues similar to this from some of the other coils they supply.