How can I tell if I have an auto coil or a marine coil. I've posted this problem a few times before but this just came to mind. My engine (1967 Johnson VXL-13A) is having trouble getting up to the high end on the tach but that's not what I ned to know, I think that may be a prop issue. I've gone over the entire engine and made sure everything checked out. What I need to know is if someone has put an auto battery ignition coil on my motor will it run just fine for a while and then all the sudden without much warning start to bog down to the point that it dies if I continue to try to tun it at full throttle? If I back the throttle off to idle and let it run for a few minutes I can then get up and go again but not as long as I did the first time. It seems like the longer I let it set at idle the longer I can go when I throttle up. I know that an auto coil has an internal resister and the coil I'm supposed to have has an external resister wire. So would adding an external resister wire to an auto coil cause it to run just fine for about 3-5 minutes and when both resisters start to heat up and begin to cut the current off bog the motor down down. I know this may sound like a stupid question but I haven't had much experience with battery ignition systems. What would happen to my coil if i remove the resister wire and it is a marine coil. Would it fry it? Is there a difference in the appearence of the two coil if they are both the cylinder types? After everything I've done to try to figure out this problem it almost seems too simple that this could be the cause.
