1985 90 HP JOHNSON NOT IDLING

[wantaghmako]

I just picked up a Boston whaler with a 1985 90 hp Johnson motor, when I started it I had to keep it running with the throttle up. I ran it and it got up to 4500 rpms for a short time then it stalled. I had a hard time getting it to the slip because it kept stalling. Now I can get it to turn over with the throttle up bet can’t keep it running. The compression is all at 90.it ran ok in my driveway for ten minute. It also doesn’t seem to get hot. It will stay running at a high rev of about 2500 to 3000 rpm.<br />Thanks Kevin

 

[rodbolt]

Re: 1985 90 HP JOHNSON NOT IDLING

if compression AND spark are good start hunting fuel problems. usually caused by trash/varnish in the carbs.<br /> also test the alarm system to insure the horn actually works.<br /> does it help to occasionally bump the choke while its running ?<br />nothing like running an outboard thats telling ya its sick, most outboards that are forced to work when they call in sick die rapidly. you can have good compression and ten min later no compression.

 

[B.autry4711A]

Re: 1985 90 HP JOHNSON NOT IDLING

Wantaghmako,<br /><br />How old is the gas in the tank. If you just bought it who says if the gas is fresh it might be stale and that is why it is running poorly. If I was unsure about that gas I would get rid of it flush out the tank and get fresh oil TCW3 rated outboard oil and fill up the tank with fresh 87 octane fuel and I would probably do a decarb with Seafoam. Let me know what happens if you do this, I would.

 

[rusty bolts]

Re: 1985 90 HP JOHNSON NOT IDLING

Hello ,this is my buddy's boat ,that we looked at this morning. Fresh gas and new primer bulb and gas line ;helped a little. the fuel filter/ in the cowl before the vro pump was only half full unless you pumped the bulb and then it would fill ,Pumping the primer bulb did not have any effect on the motor other then that.. The motor would run most of the time if you choked it on and off,with the throttle inched up a bit in neutral,when the throttle is pulled back to neutral it will idle down and stall .The motor runs cold, and from the looks of the motor head gasket were done ,water jacket gaskets , and water hose, in the back ,It may have had a over heat problem it the past and the thermostats were left out,also the gasket on the carburetors look new .Boat was perished at a large dealer, so we thought it was good to go,May be a fuel / vro pump , I have a spare. any held would be great Rusty