I have a 6.5hp briggs on a poulan pro mower. The coil will spark a few times and quit, spark and quit.

[moodymac]

I have disconnected the ground wire with no effect. Tried a new coil from another project (same coil type) and got the same results. I cleaned all contact points on both the mower and old coil. Set both coils to .012 inches. Ran ohm test on old coil (4.3) and new coil (6). Checked magnet on flywheel, and it seemed strong, however I know of no other way of testing it. Ran ohm test on ground wire and got no resistance. The brake switch was open when in run and closed when off. Am stumped, any help would be appreciated.

 

[Scrubcadet10]

what method are you using to check spark?

 

[Rivets]

Sounds like you may have a bad ground. Please post all engine numbers. What did you set the point gap at?

 

[StarTech]

Good question as if using the same old plug it might be defective. Always use a known good. New doesn't always mean good plug.

 

[moodymac]

I checked the spark with an inline spark meter (light). Turned the engine over with spark plug out and connected to the spark indicator. With a separate jumper wire run from the engine to the plug for the ground. The coils were checked with an ohm meter set at 20k. Complaint was the engine either would not start, or occasionally started then immediately died. The new coil on hand acted the same as the original. The new plug acted the same as the original. The ground wire to the coil was at first connected and then disconnected with no difference. The engine is a Briggs Quantum on a Poulan Pro self-propelled push mower. The spark tester shows spark when I first start the rotation of the flywheel, then quits. It starts back if I quit and restart the rotation, then quits again. The spark last anywhere from one to three seconds. Could it be the flywheel itself? How do I check it other than to see if iron sticks to the magnet?

 

[Rivets]

I’d set the armature air gap to .008 and see if there is any change. Very seldom do magnets go bad. Finally, checking resistance on today’s coils is meaningless, as they contain Hall effect triggers which you need high tech equipment to check.

 

[Fish]

Are you spinning the flywheel with a drill, or using the pull starter?

 

[moodymac]

I’d set the armature air gap to .008 and see if there is any change. Very seldom do magnets go bad. Finally, checking resistance on today’s coils is meaningless, as they contain Hall effect triggers which you need high tech equipment to check.

I reset the gap to .008 and no change. Put the new coil on the machine I had purchased it for, and it works perfect. Also used the spark plug on the bad machine, and it also works perfectly on this one. And I recheck the pull of the magnets on both machines together, and they appeared to have the same strength.

 

[moodymac]

Are you spinning the flywheel with a drill, or using the pull starter?

Both.

 

[Rivets]

When you say “works perfect”, does that mean problem solved?