1979 Johnson 150 Seahorse

billsleek

Recruit
Joined
Mar 22, 2012
Messages
2
I have a 1979 Johnson 150 Seahorse. I had it out on the river today and it was running strong then just shut down. I could restart it but then I put it in gear it died again. had to use the trolling motor to get back to the docks.

Every time I started it, it would idle ok but then I put it in gear .. poof, dead again.

any suggestions?

Thnx,
Bill Sleek
 

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: 1979 Johnson 150 Seahorse

First... Check compression. What are the cylinder readings?

Second... With s/plugs removed, check the spark which should jump a 7/16" gap with a strong blue lightning like flame... a real SNAP. What do you get? Note that the 7/16" gap is important.
 

billsleek

Recruit
Joined
Mar 22, 2012
Messages
2
Re: 1979 Johnson 150 Seahorse

First... Check compression. What are the cylinder readings?

Second... With s/plugs removed, check the spark which should jump a 7/16" gap with a strong blue lightning like flame... a real SNAP. What do you get? Note that the 7/16" gap is important.

Thnx Joe, I will be checking them tomorrow
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 1979 Johnson 150 Seahorse

Probably not running on all 6 cylinders. If you have any weak ignition components they will tend to fail once the engine heats up to normal operating temps. That is a dual power pack engine with 6 spark plug coils. All of these may be swapped for testing puposes.
 
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