Briggs and Strattion Sprint 375 has no spark

Hello folks,

so I got a mower engine to repair, the one stated in the title. It won't start, air filter is clean, carb works (sparkplug is wet)... I replaced the sparkplug with one from a mower that I confirm that works, and the engine still has no spark, yes I did test the sparkplug.

I removed the engine cover, the coil/magnet looks like new, has no rust on it just like the flywheel. The thing that I noticed that the gap between the magnet and flywheel is extremly small, I measured with a gap meter and I could hardly fit a 1mm blade between the magnet and flywheel, also the flywheel looks like it's not centered (rotating the engine shaft changes the gap between the magnet and flywheel) and at some points it looks actually like the magnet touches the flywheel. Is the gap supposed to be larger?

Or is the ground wire from the magnet shorting out (not allowing to create spark). I can confirm that the magnet does it's job, used a multimeter on the spark plug socket and on ground, and rotating the shaft shows a few volts.

The start-run handle does it's job, it connects and disconnects the ground wire when needed, also activates the brake.

The info I got about is that the mower wouldn't start after the mower got hit (?). Now I don't know if that means that it hit something in the ground with the blade, or just bumped into something.

Anyways, do you have any suggestions? Thanks in advance! :wink:

if the blades hit something i would suspect a sheared flywheel key.
it holds the flywheel in alignment with the crankshaft to provide spark at the correct time. when the key shears it throws off ignition timing.
It is located under the flywheel nut.

Scrubcadet10 said:

if the blades hit something i would suspect a sheared flywheel key.
it holds the flywheel in alignment with the crankshaft to provide spark at the correct time. when the key shears it throws off ignition timing.
It is located under the flywheel nut.

Click to expand...

But even if the ignition timing was off I should get spark but not in the correct time?

Flywheel to coil gap should be .010” or approximately 2.5 mm.

Okay I'll try that gap.