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shannon3115 · Mar 22, 2011, 05:33 PM

16.5 hp kohler motor on a craftsman mower. Can the flywheel magnets go bad? If so how do you check them. We have replaced coil,elec box, switch. The gap is 0.010 on the coil. It's not on upside down. The keyway isn't sheered. My dad and I are usually pretty good on this kind of stuff and the magnets are the only thing we can figure. We've eliminated all the safety switches.

Thanks
Shannon

smoothy · Mar 22, 2011, 05:35 PM

It does happen. But not often. If they are hit hard with a hammer. Much like when trying to premove a flywheel in an improper manner... that can do it.

I have seen this happen on other types of magneto fired engines.

I'm not sure how you would test for a weak magnet however.

shannon3115 · Mar 22, 2011, 07:18 PM

The mower was running, went inside to get my hat before I started and when I came back out it died. Parking brake on, switch on. Thought it ran out of gas. Wasn't it. Checked and had very weak spark . Replaced spark plug. Not it. Replaced coil as the mower is 10 years old, thought it might be time. Not it. Local mower shop said little brain box. Not it. Bypassed all the switches. Not it. It has completely drove us crazy and the only thing left is the magnets. Would a stator have anything to do with this. I know its for charging, just grasping for staws.

Thanks
Shannon

shannon3115 · Mar 22, 2011, 07:19 PM

The mower was running, went inside to get my hat before I started and when I came back out it died. Parking brake on, switch on. Thought it ran out of gas. Wasn't it. Checked and had very weak spark . Replaced spark plug. Not it. Replaced coil as the mower is 10 years old, thought it might be time. Not it. Local mower shop said little brain box. Not it. Bypassed all the switches. Not it. It has completely drove us crazy and the only thing left is the magnets. Would a stator have anything to do with this. I know its for charging, just grasping for staws.

Thanks
Shannon

smoothy · Mar 23, 2011, 05:02 AM

Charging systems on these typically are completely separate from the ignition so I doubt that's it.

Never heard of a sudden failure of the magnets... but it could have been gradual and finally hit that threshold it stopped working.

Where I saw this happen were on much older engines, 30+ years old. But since you eliminated everything else, like the plug, coil and everything else, it does seem to indicate that is possible.

I assume since it wasn't mentioned... you have no spark at all at the spark plug or it's a weak yelllow vs a sharp blue.

crigby · Mar 26, 2011, 09:25 AM

Hi,
If you have that "Smart Start" module, well it "sucks" and could be the critter. Other than that, separate the engine from the frame (unplug the ignition ground) and I will bet it will start. Last machine I fixed took less than 1 minute this week, but it was not a rider; they take about two.
Peace,
Clarke