1985 Johnson 40hp no power

[Bonstrosity]

I was out on my boat the other day fishing, the motor ran well till the end of the day. I fire it up and start driving at about 3/4 throttle moving up to full when I suddenly lost power. The engine would not rev up past about 1/4 throttle. It would only bog. If I kept the throttle in a more open position I would get a surge of power every once and a while then it would bog back down.

I've seen similar issues with dirty carbs, pushing the enricher button only made it bog more and the primer bulb was firm, so I do not see it as a fuel problem.

Where should I start trouble shooting? i have a manual, I'm thinking testing the stator, power pack and coils.

 

[tx1961whaler]

Re: 1985 Johnson 40hp no power

Check the compression, then the spark at the plug wires using a spark checker. Then if there is a problem with the spark on one of the cylinders work your way back. Check the coils by swapping them and seeing if the problem follows a particular coil.