81 60hp Johnson lower carb won't go until you spray carb cleaner

[Quahog]

Hello!
I have been working on this dinosaur for a friend. His complaint was that the boat would not throttle up. last year I remanned the carbs and he never used the boat. This year he had the same problem so I had him bring it to the pond it was very hard to start but cycling the choke I was able to get it going and when it was warm it started a little better (a little). I had him throttle up and I gave it a shot of carb. cleaner in the top carb and the engine stumbled a shot in the lower carb. the motor picked up rpm and went like it should. I had him buzz around the pond and it ran great. When I had him bring it back to idle and throttle up again it would not go until I gave it a shot of carb cleaner (just a quick little pssht) then off she would go. I am rebuilding the carbs again now. Any other ideas? I checked compression last year I don't remember what it was but it was equal between cylinders.

 

[clemsonfor]

Re: 81 60hp Johnson lower carb won't go until you spray carb cleaner

no carb cleaner it cuts the oil!! I HAd to say that since i know someone would. I have the same motor. That either means that the bottom cyl is not firing at first or weak and the extra fuel is allowing full power or that the top cyl has a weak spark. I personally would rebuild the carbs and pay close attention to the needles and seats and the float adjustment. This is only a 2 cyl so if one cyl was not fireing at all i dont really think it would sound right or allow him to "buzz" around the pond? You can always pull the plug wires one at the time while running to see if you get a change in sound from killing the cyls one at the time.

-nate

 

[Quahog]

Re: 81 60hp Johnson lower carb won't go until you spray carb cleaner

Thank you for the reply. I am pretty sure it has something to do with fuel delivery. The quickest little shot of the dreaded carb cleaner "jump starts" the carb and it works fine until you return to idle. I have not had a chance to test it with the re-remanned carbs. Hopefully that will take care of it!

 

[Falcon89]

Re: 81 60hp Johnson lower carb won't go until you spray carb cleaner

Don't know if you have solved your problem yet but I am dealing with the exact same issue on my '73 Johnson 55 hp outboard. I took it to a professional mechanic and after $300 of troubleshooting he determined that the throttle shaft was worn on one of the carbs. What happens is when the throttle is at idle, the throttle plate is in the "closed" position, drawing in mostly fuel. When the throttle shaft is worn, it draws in air around the throttle shaft and therefore leans out the mixture too far to run properly. By spraying carb cleaner or fuel into the throttle, you are supplying much needed fuel in a too-lean mixture situation. When you open her up, the throttle plate now opens, allowing more air and thus rendering the leak insignificant and the cylinder sputters to life. After a very frustrating and expensive venture of purchasing another set of carbs off of ebay I discovered that they have the same problem!!! So my next step is to bore out the throttle shaft holes and install bushings to restore the tolerances back to where they should be. I'll let you know how this works for me.

 

[Silvertip]

Re: 81 60hp Johnson lower carb won't go until you spray carb cleaner

If those carbs had idle mixture screws, the lower carb may be set too lean which prevents the engine from transitioning from idle to mid range or full throttle. Richen the mixture on the low speed.

 

[5150abf]

Re: 81 60hp Johnson lower carb won't go until you spray carb cleaner

Year old thread, June, 12 2009

 

[Faztbullet]

Re: 81 60hp Johnson lower carb won't go until you spray carb cleaner

Old thread but Johnson didnt make a 55hp until 1976....

 

[Bob_VT]

Re: 81 60hp Johnson lower carb won't go until you spray carb cleaner

Time to lock this one up