Reply To: 58 18hp conked out

[jeff-register]

Once I had magneto problems with a Mercury. Did the same as you did & it would misfire. Looked at the   magneto again & the points turned gold they  got so hot.

I found a current reverse from one coil to the other due to a bad bonding wire which the factory never installed. I ran a jumper wire from the magneto plate to the block & fixed the problem. I had cleaned the mating surfaces between the magneto plate & block clean enough to eat off of but the light film of petro gel I used was enough to insulate the two from each other. It was tight enough fit when new to have a good connection but now 40 years later. All the energy from coil 1 was back feeding to coil 2 cooking the points not firing the plug like it should of. Try running a jumper between the magneto plate & the block. My motor ran very well after i installed a bonding wire. Petro Gel is an inert lube I used in many places because it doesn’t dry out.

Good Luck!!