88 Johnson Not Starting/Cutting out

bostonmike

Cadet
Joined
Apr 9, 2007
Messages
8
I have an 88 Johnson 90hp V4. On a few separate occassions, I've been able to start it up with no problem with airmuffs on. After towing, I cannot get it to start. If I let it sit for about an hour, it starts up with no problem, first turn of the key. After running at various speeds and RPM for about a half hour it dies and I can't get it started again.

I've bypassed the kill switch as a test and replaced the plugs and wires. I don't think that it is electrical because I have this problem starting it cold after towing as well as after running for about 30 minutes. The only thing that fixes the problem is letting it sit for over an hour.

Can this be caused by not having the valve on the fuel tank open? I realized that I have not had it open and after towing home the last time, the tank was dented in on top like there was a vaccum effect or something.

Any help would be greatly appreciated, this is my first boat so i'm learning as I go.

Thanks.
 

Bilge Monkey

Cadet
Joined
Apr 8, 2007
Messages
16
Re: 88 Johnson Not Starting/Cutting out

yes you have to have the vent open on the gas tank.while running
 

Walker

Captain
Joined
Jun 15, 2002
Messages
3,085
Re: 88 Johnson Not Starting/Cutting out

z
I've bypassed the kill switch as a test and replaced the plugs and wires. I don't think that it is electrical because I have this problem starting it cold after towing as well as after running for about 30 minutes. The only thing that fixes the problem is letting it sit for over an hour.




Thanks.

No offense, but thinking its not electrical isn't good enough for diagnosis of your problem. You need to do a spark test when it won't start to be sure.
 

bostonmike

Cadet
Joined
Apr 9, 2007
Messages
8
Re: 88 Johnson Not Starting/Cutting out

OK, I will try a spark test as well to make sure, probably better never to assume!

If the fuel tank vent is shut, would that cause a problem trying to start it as well? I'm assuming if the tank has sat for a while it will lose pressure, but if it was just trailered and bounced around then the pressure would be pretty high.
 
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