97 Johnson shuts off after warming up

J

joefishin

Recruit
Joined
Apr 12, 2008
Messages
5
My 1997 Johnson cranks fine and runs fine to start with.....
But after running it near or at WOT for 5 to 8 minutes......it start shutting off....and starting back. Constantly on and off, on and off. I can back the throttle down to about 30%........and it runs fine. I can let it cool down and it runs fine until it warms back up.......then it's on and off, on and off.

I put a new fuel pump on it. And new spark plugs. Still does it. What can it be?
 
Joe Reeves

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: 97 Johnson shuts off after warming up

When this takes place, does the fuel primer bulb have a tendency to collapse somewhat? If so, that would indicate a fuel restriction.

Also visually check the stator under the flywheel. If the large black coils are oozing and dripping a substance down on the powerhead, that would result in weak, and eventually no ignition.
 
J

joefishin

Recruit
Joined
Apr 12, 2008
Messages
5
Re: 97 Johnson shuts off after warming up

thanks Joe.

The primer bulb is tight when shutdown occurs.. And the stator has been replaced.
 
B

bgbass.1

Chief Petty Officer
Joined
Aug 1, 2007
Messages
558
Re: 97 Johnson shuts off after warming up

My 95 rude was doing the exact same thing it drove me nuts. Follow tan wire on back left side going into motor and unplug it if that fixes the problem you need a new temp. switch its located behind that plate. Mine had corroded and sent a false overheat signal and would shut down.
 
J

joefishin

Recruit
Joined
Apr 12, 2008
Messages
5
Re: 97 Johnson shuts off after warming up

bgbass.........I found and unplugged the tan temp switch wire. It still cuts off when the motor worms up.

Could it be the coil?
 
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