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1998' 90HP Johnson idle problem

C

carolinaflare

Contributing Member
I have a 90 HP 1998 model (J90SLECM) . I just rebuilt the PH and rebuilt the carbs. New pistons (original size) new rings, (original size). and so forth.

I am finding that it is burning a lot more fuel and oil than i remember before. Even before it needed rebuilding.

I have problem with it at idle. If i start it and run it for a while and then shut it down (at the sandbar) when I try and re-start it it turns into a hard process, and them it wont idle worth a crap. I have to run harder to keep it running. Most of the waterways here are manatee zones (slow speed) so im sure its loading up.

Im still using the VRO pump but im thinking of disconnecting it and just pre-mixing anyways. Could this help?
What should I do about the fuel and oil economy?
 
Re: 98' 90HP Johnson idle problem

This a ian 60 deg motor, I had the same problem and this is what I got from Bill, about heat soak.

Heat soak is when the heat of the motor rises under the hood after running for a while then shutting it off. The fuel boils from the carbs and that makes for hard starting and no power until the engine is run (if it stays running) for a while to cool down the venturis.

The 60 ° motors have this problem more than others because the carbs are at the sides of the motor where the block is hotter.

Ethanol fuel makes the problem worse. It's best if the owners start the motor and let it idle for several minutes to stabilize the under-hood temps. They may have to squeeze the primer bulb, too, at first.
__________________
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Bill Grannis

field edtior - Trailer Boats Magazine

service manager - Bluewater Boats, Inc.
 
Re: 98' 90HP Johnson idle problem

Nice, that would make scense. I do have to pump primer before I can restart. even if it has only been off for 5-10 minutes. Its a pain in the A$$ when your trying to leave the sandar and in between boats and you only have that split second to start and go when there are 100 boats anchored together.
 
Re: 98' 90HP Johnson idle problem

It also will try and stall when you slow it down to come to the dock after about a 20 min fast idle no wake zone, (2200 rpm) . every time.
 
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