1988 90HP Johnson running poorly

[pochejp]

I am having a problem with my 90hp Johnson running poorly during take off from idle. Once the boat gets up on plane it runs fine. Let me give a little history. I have just replaced my transom on my boat and had the motor removed and stored in my garage on a stand for a few months (3). I remounted the motor and connected all the linkage and wiring like it came apart when I completed the transom. This was the first outing since the motor was remounted. The motor ran great prior to the removal from the boat. I'm thinking that the throttle linkage is not calibrated correctly. I was reading some of the posts here and came across a statement by Dhadley "Anytime you have to hit the primer (not a choke on that motor) to keep it going, that indicates a lean condition. It could also indicate a sync & link problem. make sure all the linkages are set by the book". What is the correct sync and linkage setting for this motor? Is there any rule of thumb measurements? Idle RPM's? Maybe the carbs are gummed up? Would it run fine at high RPM's if that were the case? Thoughts?

 

[Walker]

Re: 1988 90HP Johnson running poorly

First off, are you running fresh fuel?? If not drain your tank and flush the fuel line and give her another try. If you did nothing more than disconnect the throttle cable then your link&sync didn't change. I'd say you probably have fouled carb/carbs from bad/evaporated gas in the bowls. Your best bet would be to tear them down, soak them in a suitable carb cleaner and rebuild them with new kits.

 

[Pony]

Re: 1988 90HP Johnson running poorly

I agree with Walker.........plus even if carbs arent the problem a good cleaning/rebuild wont hurt anything.<br /><br />How di you store it. 3 months with old non stabilized fuel in the bowls, non fogged would gum up a little most likely.

 

[rodbolt]

Re: 1988 90HP Johnson running poorly

I dont reccomend soaking OMC carbs, use a good spray type cleaner and safty glasses and gloves. <br /> but sounds like your carbs got a little funky due to solids in the fuel bowl. does not take much and the idle pickup tubes are clogged as are the main jets. its very possible to have that motor run about ok at high speed and not idle as the high speed and idle circuits are almost seperate. if your carbs have plastic bowls carefully check the edges with a straight edge for warpage, they like to warp and then run pig rich and nasty, classic symptom is it idles better as the trim goes up.

 

[BoatBuoy]

Re: 1988 90HP Johnson running poorly

Originally posted by rodbolt:<br /> I dont reccomend soaking OMC carbs

That begs the question, is there a reason?

 

[tashasdaddy]

Re: 1988 90HP Johnson running poorly

Jason, i don't know if you do it,but i was taught when i ws a kid to disconnect (on turn off) the gas and let the engine run until it stops. apparently it works to keep the carbs from gumming up.

 

[TxShorty]

Re: 1988 90HP Johnson running poorly

OMC carbs that are plastic, or the carbs that have plastic float chamber bowls shouldn't be soaked. The plastic will warp and cause major problems for you. Have soaked many all metal OMC carbs without any problems.

 

[pochejp]

Re: 1988 90HP Johnson running poorly

Motor was run with fresh fuel. I stored it without stabilizer. It probably had fuel in the carbs during storage because i never run the carbs dry before putting the boat up after usage. I guess I will have to tear down the carbs and clean the jets and bowls. I'm not sure if the bowls are plastic or not.

 

[Walker]

Re: 1988 90HP Johnson running poorly

I've been soaking all OMC carbs, both plastic and aluminum body, in Chemtool Dip, for years and have never had a carb part warp or melt or in any other way damaged by the soak.