1992 40HP Johnson no idle

[Ibanez1977]

I just bought a 1992 Tracker with a 40HP Johnson oil injected that the owner told me needed to have the carbs rebuilt. It wouldnt idle. I rebuilt the carbs (floats set even with carb when turned upside down), new plugs, primer bulb, new gas, and still won't run. I reset linkages to service manual specs. Motor runs rough and surges. Coughs like its lean, but adjusting Mixture screws seem to have no effect on engine. When i do get it to idle, butterflys on carb halfway open and idle adjustment screw buried. Primer bulb stays full like it should. Has to be cold started with almost full throttle. Any help greatly appreciated.

 

[Joe Reeves]

Re: 1992 40HP Johnson no idle

Ibanez1977.... If you have compression and spark on both cylinders, I would assume that you have overlooked something in the carburetor section, possibly the high speed jets and or the passageway through the small copper tube that leads from the float chamber to the slow speed passageway. They must absolutely be perfectly clean.

 

[Ibanez1977]

Re: 1992 40HP Johnson no idle

thank you very much for your reply. I know the high speed jets are clean, as i took them out and cleaned them. I did not take that copper tube out, though. Should i have? The guy i bought the boat from has been having this problem all last year. I did originally forget to reinstall the air idle orifice in both carbs but i figured that out and they're in now. Ill definitely recheck the tube. Is there anything else you or anyone else can think of in addition if thats not the problem, I have to travel about an hour and a half to my boat

 

[Ibanez1977]

Re: 1992 40HP Johnson no idle

i was thinking about this last night. The motor will rev really high and I can hold it there, which makes me think (perhaps wrongfully so) that i don't have a fuel delivery problem. It will not idle normally. With the butterflys on the carbs being open just to get it to idle, would it be safe to assume a possible restriction somewhere in the air idle orifice passageway? Could just one of the two carbs be causing my headache and, if so, how could i pinpoint which one. Is there any way the oil system could be causing this? I'm probably going to bypass it and mix gas when i get the motor running right. Would it be a good place to start with the mixture screws full lean, rich, or in the middle? With the boat being so far away id like to have a few ideas to go down there with. Thanks for any help.

 

[james roach]

Re: 1992 40HP Johnson no idle

Take the carbs back off and unscrew the jet under the needle and seat assembly. Soak the carbs in cleaner overnight and then blow out with compressed air. Clean out that little jet you unscrewed and put back together. This is a very common problem. It does no good to rebuild the carbs if you dont clean out the passages that remain. I personally have never rebuilt a carb. A thorough cleaning was all that was necessary. Good luck.

 

[Ibanez1977]

Re: 1992 40HP Johnson no idle

i guess im off to the lake tonight to take off the carbs. thank you very much

 

[Ibanez1977]

Re: 1992 40HP Johnson no idle

Well i took both the carbs apart again and, sure enough, in one of the pick up tubes was a glob of something I missed the first time around. I didn't realize it until i compared the two and saw one had a hole running through it and the other was plugged up. I cleaned it out and made sure every passage and orifice was totally unrestricted. I put them back on the motor and it runs better and sounds healthier than it has for me yet and runs at a lot lower RPM than i could get it to before, and the butterflys are almost full closed and running, verses half open before, but it still won't idle as low as it should. In addition, i let it run for about 10 mins when an alarm went off, and i don't think it is the oil because this alarm was solid, verses my manual says the oil alarm should be 1/2 on 1/2 off. Impellar is operating correctly, if that matters. Squeezing primer bulb has no effect on idle. It doesn't smell rich and it doesn't backfire like its lean now, but it still won't drop down to a good idle speed without dying. I can gently feather the butterflys and keep it running. I'm as confident as i can be that the carbs are clean, what should i do now<br /><br />I think im ready to disable the oil injection, but i read that the oil on some models lubricates the pump. What all do I have to do to correctly remove the injection system? I know there is info on this site about disabling the injection, but i would like to know with my specific model what i should do.Any other ideas on the idle? I really appreciate the help so far and hope one day i can return the favor!

 

[Ibanez1977]

Re: 1992 40HP Johnson no idle

just added a new fuel filter today...probably should have done that earlier but either way it had no effect on the idle. Any suggestions???