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Discussion Starter #1
I'm an "old rat" that's been around small engines for many years. I was really good at the old point type engines but, over 70 now and I've run across one that has really messed up what's left of my mind. I hope someone can help me solve this puzzle: Briggs 18hp 2cyl L Head. No spark, disconnected kill wire from magneto - no start. Ordered new mag, no spark, no start. W/ohm meter, kill wire terminal on mag shows short to frame of mag. Company replaced new mag with another new one - same thing-kill wire terminal shows short to frame of mag with kill wire detached. (Pulled and checked flywheel key - OK) Is this magneto supposed to be insulated from engine block? I've been around small engines for a while but, this one has me totally bumfuzzeled. Please help!
I will try to be of some help to others as the occasion arises. Thanks for allowing me in.
 

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Hello, Gooseneck, and welcome to MTF. Glad you found us and jumped in. I am sure you will get some good assistance here before too long. Enjoy your visits here at MTF!
 

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The primary windings (arms that are gapped from the flywheel magnets) will have continuity with the kill switch lead. It's the secondary windings that will not.

What type of machinery is this engine used on? Can you post engine/equipment model numbers? It could be a faulty ignition switch, stop switch connection on throttle control panel, shorted wire, invalid safety switch etc. Also a possibility that the magnets in the flywheel have lost their strength, but is not a likely issue.
 

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Air gap right? Could be rusted flywheel magnets, as far as i know the coil doesnt have to be isolated from the block. Since you disconected the ground it cant be a bad switch.
 

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Discussion Starter #5
Thanks everyone!
This old dog thought he knew a lot but found out that an "old dog" can learn something new. I had pulled the flywheel to check for a sheared key, found it OK and replaced the flywheel. I didn't know that the flywheel nut had to be torqued to 65 lbs and if not it will shear the key. Well, I didn't and it did. Anyway, the problem is solved and engine is running smooth. I'm enjoying this forum and will continue to read posts. I now doubt if I am smart enough to contribute anything but you never know. Thanks for allowing me in.
 

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WELCOME GOOSENECK! Yuppers us old dogs can learn new tricks!
 

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"I had pulled the flywheel to check for a sheared key, found it OK "

"I didn't know that the flywheel nut had to be torqued to 65 lbs and if not it will shear the key. Well, I didn't and it did."

"Anyway, the problem is solved and engine is running smooth. "

Apparently you replaced the flywheel key, torqued it properly and now it runs. That still does not explain what the problem was in the beginning since you tried two, maybe three coils and no spark, key was OK when you pulled the flywheel the first time, so what was the problem?

Walt Conner
 

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Had a engine that wouldn't start because the key switch's female spade terminals were not insulated and two bare female spades manged to get together.
 

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Discussion Starter #9
Hey Walt.

The original coil was bad I believe. I was mowing, stopped for lunch and when I killed the engine it backfired rather loudly. It would not restart so I checked for spark and did not detect any spark on either side ( I disconnected the kill wire). Having some limited experience, I pulled the flywheel and found the key intact and the flywheel in its proper place. Right or wrong this confirmed for me that the coil was bad. I replaced the coil, took an old spark plug and clipped the ground lug back and had what I thought was a weak spark. It ran roughly for a few seconds and died again. I just KNEW! that the new coil was bad? But, before I replaced this coil, I pulled the flywheel again and found the key sheared. Went to town (20 miles) for an new key, replaced it and it started, ran very roughly for 2-3 minutes and died. Pulled the flywheel again and started pulling my hair. Then I went online, another forum, and saw where a fellow named Walt (was it you) told someone to torque the flywheel or it would continue to shear keys. If it was you, you solved my problem. It runs great now, I believe better than before it first died. Anyway, if it was you, a great big THANK YOU!!!:thanku:
 
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