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Discussion Starter #1
I have a Craftsman lawn tractor with the 19hp Briggs twin 42E707. It is loosing power and firing intermittently on the Left side only. This is a single coil design, and has 105, and 110 lbs compression right and left. When power is lost I can smell unburned fuel and the left plug is wet. I installed new plugs and got about 5 hrs service. I did a spark test and noticed that I had no spark on the left until I released the key. Someone in another thread suggested the possibility of a short in the ground wire or a bad diode. The manual that comes with this is poor at best. Where would I find that diode? Any other suggestions?
 

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"19hp Briggs twin 42E707. "

"Someone in another thread suggested the possibility of a short in the ground wire or a bad diode. "

Not a bad diode on this engine. That applies to "V" twins that use 2 ignition coils.

Clean the coil mounting area, unplug the Kill Wire at the bottom of the coil, set proper Air Gap and see if any of these things did any good, if not, probably bad coil (CDI)

Walt Conner
 

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I agree with Walt, these opposed twin coils are notorious for dying when hot after they get some age on them. Intermittent firing of one cylinder to no firing for either cylinder. Only fix is replacement of the coil.

Good Luck!

Seth K. Pyle
 

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With a NEW coil. Installing a used opposed twin coil sets you up for the same thing you are dealing with now.

Seth K. Pyle
 

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Discussion Starter #5
Thanks Guys, I think you are right. After sitting for a day It ran great for about 5 minutes. Then quit on the right. So cold I could touch the exhaust manifold by the time I had it back in the garage. I put on a spark test light. Strong light while running on the left, very weak on the right.
 
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