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adamico18

weak spark

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adamico18
hey guys my 69' big ten with the 243431 briggs seems to be giving me a couple of problems the most recent is now i have no spark or at least a weak spark, the points/condensor/magneto armature along with the wiring from the points to armature are only about 2 years old,i cleaned and gaped them @ .020, when i check for spark there is no visual spark on the plug or if i try getting the spark plug wire to arch there's nothing.If i touch the wire though i will get shocked 2 out of 5 times i try the other 3 nothing at all, i guess my question is,is my condenser? or points just bad? im sure its something simple or something i overlooked appreciate any input

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powerking_one
Mike, I would check for a partially sheared flywheel key. Unless the flywheel nut is really torqued to spec, all it takes is one backfire to cause this condition. If there are any marks of shearing, replace it. Tom (PK)

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adamico18
tom, is that a common issue with these motors, its something ive heard of before but makes sense as sometimes when i accelerate the motor will spit and sputter the get up to rpm and other time it will run a at 3/4 throttle for 2 hours then when you go to idle it down it shuts off and takes a alot of cranking and or pulling to get it going, also will the play in the flywheel be visible or do i have to remove the flywheel and visually inspect the key? thanks

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ka9bxg
I hated to do it but on my 16 hp briggs it would quit running in the winter. I put on a coil out of a Kohler in. It is not correct but was sick of it not running. I had gone through all the same stuff that you did with out it running better. Now it starts easier and runs better in the winter.It does have a loader bark to the exhaust and does back fire more but does run good.This is a worker so pretty is not important to me. Hope you fine your problem. Bob

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adamico18
cleaned the points again,re-gapped, replaced them plug and it started right up, after about 10 minutes of running it backfired and died out. i pulled them plug out and checked for spark, and the it would have good spark for 15-20 seconds then no spark for maybe 2-3 seconds then it would be good for 30 seconds then nothing, really sporadic. now im wondering if its worth the 20-30 bucks to replace the points and condensor. when i cleaned them they didnt look bad but one side looked like it had a small "crater" i guess you could call it about the size of a needle head on one of the contacts, again any help appreciated

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RayS
I definitely would remove the flywheel and check the key. If it is not that it is more than likely the coil. When I sheared a flywheel key on my 16hp it would not start at all. Is it wire possibly shorting out between the block and where it is going into the points cover?

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dhardin
I agree with Perry, to check the magnet on the flywheel. It could have some rust/dirt built up and causing the coil to get a week charge. Also the coil itself may be rusty and dirty and not handling the charge. Also a bad ground/dirty or rusted. Best bet for sure is to check the air gape and make sure it is to specs. Just a small amount of extra gap will really cause it hard to start. Before you have done all this check the coil with a ohm meter and if this is within specs look some where else. Most the time with a week coil a meter will tell you this fast, and a new coil is in order.

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adamico18
i have an ohm meter not 100% sure how to use in order to check the coil i assume i need a good ground then attach the + wire of the meter to the end of the spark plug wire and then what would be a acceptable reading on the meter to decide whether im in the good thanks again guys

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MrSteele
From an old auto mechanic. If your points are burning on one side as it sounds, you need a condenser. also need to check the spacing between the mag and the flywheel. A business card is too thick to use, but if your mag is farther than that from the flywheel when the magnets are at the mag, your coil needs to be closer to the flywheel

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dhardin
Here is a simple guide for testing coils. Tractors motors have a rather wide range of operation. So you could have a problem coil that is within range and still fail when put into operation. But this will give you started. Good luck hope this helps. http://assets.fluke.com/appnotes/electricalpower/B0271b_u.pdf

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