1985 Johnson 90 problems HELP!!!

[ilboater26]

Hi everybody I have a 1985 Johnson 90 that im having some trouble with.The motor was recentaly rebuilt and is still in the break in period according to the mechanic that did the rebuilt he said it would take a 30 HOUR break in period which seems very long to me it has about 6 hours on it now and runs HORRIBLE. The motor is set to run very rich during the breakin, the vro was disconnected and im now running 50:1 premix. Ok the first problem is it boggs and sputters when u put the throttle down it takes for ever to rev up to WOT but once it revs up it runs alright however when on plane if you reduce the power just a little it runs like crap and starts to bog and sputter again. The next problem is that it has is it is a PITA to start and idles rough when you go to put it in gear it dies unless you realy throw it in to gear and you must use the warm up lever to do this but it has done that as long as i can remeber even before the rebuild. And it will not run slow or idle when trying to dock or trailer the boat. I dont know if this is beacuse it is still in the break in period or what. Any advise would be greatly appriciated THANKS IN ADVANCE!!!

 

[Daviet]

Re: 1985 Johnson 90 problems HELP!!!

I would forget the rebuild and trouble shoot like it was not rebuilt. Check spark, compression and the fuel delivery system. You have problems and the only way to find them is to check all the systems out. How do you set it to run rich, the carbs are not adjustable and you are running 50:1 fuel ratio?

 

[ilboater26]

Re: 1985 Johnson 90 problems HELP!!!

Thanks Daviet i was told that its running rich by the mechanic and it is running 50:1 gas to oil 6 gallons of gas to 16oz of oil premixed

 

[Daviet]

Re: 1985 Johnson 90 problems HELP!!!

Does it smoke real heavy? Could he have installed improper jets in the carbs?

 

[ilboater26]

Re: 1985 Johnson 90 problems HELP!!!

No not a lot of smoke, i have have some unburnt fuel and oil ooze out near the prop but that has only happened once when cruisen around the boat ramp i noticed it when i pulled the boat out of the water

 

[Haffiman]

Re: 1985 Johnson 90 problems HELP!!!

Let us start with 'running rich'.
Normally during break-in after a rebuild it should be 2% in ADDITION to a working VRO!
2% oil-fuel ratio is what to be used at normal operation when VRO is disconnected.
Providing that compression reads out OK and ignition works, my guess is that the mech has totally missed out on the link and and synch of the timing and carb system
Haul him back and tell him to get it according to the book.
Check if he has got an original OEM workshop manual??

 

[rude1]

Re: 1985 Johnson 90 problems HELP!!!

On new and rebuilt engines you're supposed to use 25:1. if the vro was hooked up you would be using 50:1 in the tank. With the vro unhooked you should be running 25:1 or 1 qt. per 6 gallons. Break-in period usually is about 10 hrs. or 2 tanks of gas. I would start w/ the fuel system. Haffiman is right, start w/ the link n synch.

 

[ilboater26]

Re: 1985 Johnson 90 problems HELP!!!

It was run at 25:1 for a few tanks a gas and now is running 50:1 unfortunatly taking the boat to the mechanic is not possible the motor was rebuilt in texas when my brother had it for about a year and the boat is now in Illinois:facepalm: so that is not realy an option is there any way I can check this myself, if so is it hard to do i dont have much experience with motors or am i better of having a good mechanic take a look at it.

 

[rude1]

Re: 1985 Johnson 90 problems HELP!!!

Without having much experience. I suggest taking it to a mechanic.

 

[Haffiman]

Re: 1985 Johnson 90 problems HELP!!!

First thing, invest in a proper ORIGINAL workshop manual as the link & synch of this engine is crucial for its operation.
Here:
http://www.marineengine.com/parts/p...pe=Service+Manual&Engine=395680&Model=90TLCOS

Even if you do not find a specialist in your area or you may want to try yourself it is a must.
While waiting for the manual, do a compression test and check that you have spark on all cylinders.

 

[emdsapmgr]

Re: 1985 Johnson 90 problems HELP!!!

Validate the spark on each plugwire. Easy to determine with an inductive timing light. Keep in mind that weak ignition components tend to fail once the engine heats up to normal operating temps, so make sure the engine is warmed up for testing.

 

[ilboater26]

Re: 1985 Johnson 90 problems HELP!!!

Ok i took a look at the motor this morning and did not have time to test spark or compression but found that it seems to have a small leak in one of the gas lines connected to the carb could this be the problem or dose everyone think it is more related to the timing

 

[emdsapmgr]

Re: 1985 Johnson 90 problems HELP!!!

Gas leaks are not good, but is probably not the reason it won't start.

 

[ilboater26]

Re: 1985 Johnson 90 problems HELP!!!

The motor starts but is just not running right after looking closer all of the gas line are connected with zip-ties and not hose clamps could it just be getting air in in the lines causing it to run HORRIBLE!!!

 

[ilboater26]

Re: 1985 Johnson 90 problems HELP!!!

emdsapmgr the carbs were supposedly taken off and cleaned thoroughly and were in good shape according to my brother who actually dealed with the mechanic who preformed the rebuild

 

[rude1]

Re: 1985 Johnson 90 problems HELP!!!

zip ties are standard on most older omc carbs. Leaks allow air to be sucked in causing the engine to run rough. Metal hose clamps are not recommended, manual says it could damage the hose. But no matter what you use you have to stop the leaks.

 

[jayyyy]

Re: 1985 Johnson 90 problems HELP!!!

I would forget the rebuild and trouble shoot like it was not rebuilt. Check spark, compression and the fuel delivery system. You have problems and the only way to find them is to check all the systems out. How do you set it to run rich, the carbs are not adjustable and you are running 50:1 fuel ratio?

X2, I Think you might need another mechanic.

 

[ilboater26]

Re: 1985 Johnson 90 problems HELP!!!

ok i might have fixed the gas leak and while doing so noticed a white strip of paint on the flywheel timingmarks at 28 is this what the motor should be timed at I remember reading somthing about marking the timing marks on this form when reading about link and synch. The model number of my motor is J90TLCOS if that helps. again thanks in advance.

 

[ilboater26]

Re: 1985 Johnson 90 problems HELP!!!

i also got the motor to idle perfect and it no longer dies when put into gear.

 

[AEROCOOK]

Re: 1985 Johnson 90 problems HELP!!!

Just how long ago was the motor rebuilt? If it was more than a year ago and its been sitting with old gas in the carbs they will likely need to be cleaned. If it were mine I would do a thorough carb cleaning then a complete link and sync starting with Joe Reeves timing procedure.