1978 Johnson 75 dies after a few minutes

Joined
May 27, 2009
Messages
13
Well I have been fighting this motor since I bought this boat three weeks ago. The first time I took it out it would idle around fine but would not come up on plane at all. No tach but I assume it would only turn about 2000 rpms before it would start bogging. So thanks to this forum I started with a carb rebuild thinking it was the h/s jets and still had the problem, next I put on a new fuel pump and still had the problem. Well today I finally got the bogging problem fixed when I pulled the fuel line off the motor only to discover that when the PO painted the motor they painted over the fuel fitting and the paint chips were blocking the flow to the engine. So I cleaned off the paint and she ran great. So the motor ran great for about two minutes and died and would not start at all. I pulled compression and I am 145 on all three cylinders. I used an inline plug tester and found that I had no spark on any of them. The trick is that after about 30 mins. it will fire back up and run fine. I think I am facing a bad power pack but I wanted some second opinions before I drop 100 of my hard earned dollars on one.
 
Joined
May 27, 2009
Messages
13
Re: 1978 Johnson 75 dies after a few minutes

Also I replaced the ignition switch and this did not fix the problem. When it dies I have no spark on any of the cylinders. Not sure about the stator but I figured the power pack was cheaper.
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: 1978 Johnson 75 dies after a few minutes

my bet is power pack.
 
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