1979 Johnson 35 hp loses power

Hi all, I have a 1979 Johnson 35 hp motor that loses power from wide open throttle when it's warm. It seems to lose power and bog until it shuts off anywhere from 10 to 15 minutes of wide open running. Once it shuts off, it does not want to start. 1 out of 3 times it started but it seemed difficult.. We let it sit for awhile and decided to fish where we stopped. After 20 minutes or so it started and we high tailed it to the landing. We were nearly back and it bogged down again and shut off. It's spitting water good so it shouldn't be overheating, but it seems the problem is related to when the engine has been running awhile and is warm. Any suggestions on where to begin would be greatly appreciated. I'm thinking it has to do with the coil packs or something electrical.

Re: 1979 Johnson 35 hp loses power

When it quits on you check your spark with an open air spark tester and see if it will jump a 7/16 " gap. This will prove if it's ignition or not. You have to trouble shoot this when it acts up.