50 HP Johnson will not accel past 3,000 RPM

djcvet

Cadet
Joined
Sep 11, 2007
Messages
11
This is an ongoing problem that my boat engine mechanic has still not been able to solve. With the engine "cold soaked" (sitting for a week without running)it will start okay but when I go to WOT it will not accell past 3000 RPM. If I leave it at WOT and run the engine for about 10 minutes all of a sudden it kicks in and goes up to 5400 RPM and runs fine the rest of the day, even if I turn it off and restart. I have had the carbs rebuilt, new ignition power pack installed, and the VOR pump removed and a fuel pump only installed. Still the same problem. I am almost sure it is ignition related because when I do the "cold soak" start and let it idle one spark plug lead is not firing and if I take the plug out it is soaked in fuel which tells me it is getting fuel but no spark. Any ideas at all? My engine mechanic and me are ready to use the motor as an anchor! Thanks.
 

Bob_VT

Moderator & Unofficial iBoats Historian
Staff member
Joined
May 19, 2001
Messages
26,097
Re: 50 HP Johnson will not accel past 3,000 RPM

It's ignition...... you have a bad part.

Idea......change mechanic! Get an oem shop manual and go for it.

What year and model is the 50? Need a bit more info to suggest things.....
 

eavega

Lieutenant
Joined
Apr 29, 2008
Messages
1,377
Re: 50 HP Johnson will not accel past 3,000 RPM

Definitely sounds like an ignition/electrical issue. What could be happening is that there is a faulty contact somewhere in your wiring which causing you to lose spark, but once the engine warms up, metal expands and contact is made. I don't know your particular motor, but I know the OEM manual for mine does have tests for all ignition components, but requires special tools.

-E
 

djcvet

Cadet
Joined
Sep 11, 2007
Messages
11
Re: 50 HP Johnson will not accel past 3,000 RPM

It is a 1994, model MODEL ? 50TLER.
 
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