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So i have a briggs and stratton model 100202-0472-01 that is on an air compressor. It ran before this but i decided to rebuild this engine. I lapped the valves, and honed the cylinder. Before this the engine used a points system. So i bought a magneto to get rid of all that. Its tge exact same as the coil that was on it for points but when i try to run the engine it only fires through the intake. And if you line the magnet up with the magneto its in the middle of the intake stroke. Im just wondering why this is, if there is a workaround, or if this is a simple fix im not thinking of? Everything is timed right, the dots on the cam and crank, the mag is properly spaced. But the flywheel seems way out of time.

Try reversing the magneto, as in flip it over.
if that doesn't work, check your flywheel key.

You likely didn't torque things properly, and sheared the flywheel key.

Also, put up a pic of the package that the new coil came in, it should look a little different than the old one.

The points coil engine's flywheels are different than the magnetron ones. Sometimes you can flip the coil over and it works. Sometimes not. If you have the old coil you can replace the points with a module to eliminate the points. Pretty much makes it same as a magnetron coil. Double check your key.

Like this

My flywheel key is sheered. That makes sense because it did run for a few seconds before backfiring and not running again. What could have caused it to shear so this doesn’t happen again?

What did you torque the flywheel nut to?

I did not torque it because i do not have the special tool to tighten down the clutch. It uses the pullstart clutch to hold the flywheel down

New key, clean the top of the crank and inside the flywheel taper, tighten that nut really tight. Should do it.

Thank you. Already ordered a new key and will try that. Thank you for your time!

I've played around with the timing change from points to electronic and you see some advance, motor sounds a bit different, more power. Not to sure it's good for an old motor though.

Couple things you can do. There is a hole in the top of the starter ratchet. That is for a few drops of oil to lube top of the crankshaft. If the shaft is dry it can seize in the recoil ratchet and bad things then happen. If you don't have the tool you can use a pipe wrench on it to tighten it.

Hammermechanicman said:

Couple things you can do. There is a hole in the top of the starter ratchet. That is for a few drops of oil to lube top of the crankshaft. If the shaft is dry it can seize in the recoil ratchet and bad things then happen. If you don't have the tool you can use a pipe wrench on it to tighten it.

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I had already dumped some in the cup as well as rubbed some on the crank when assembling it.

If you put oil in with the balls that will be causing problems shortly when the balls stick and not return to the center for starting. You will pull the rope but nothing will happen.