1976 75hp Stinger bogging down after 1/4 throttle.

[Keyboardman]

Hi all, 75 Stinger was bogging down and dying at anything over idle. Completely rebuilt the carbs and now it will go about 1/4 throttle then boggs for a while and will eventually accelerate and get up to speed. Once up to speed, I can slow down to about half throttle and back up to WOT. Bring it back to idle again and same thing happens. Bumping the choke while it's bogging only makes it worse. Almost seems like it's getting too much fuel? Any suggestions on what to look at now? Thanks.

 

[F_R]

Very common problem.

Disconnect the throttle cable at the motor end. Now grab the lever with your fingers (where the cable was attached), and observe the timer base advance as you move the bottom end of the lever (not running). It should go to full advance with very little movement of the carburetors. It is only when it reaches full advance that the carbs make significant opening.

However, if the timer base is sticky, it will lag while the carbs open too soon. If it does that while running, it will fall on it's face, maybe even stall. Cure is get rid of the stickiness by cleaning and relubing the timer base mounting.

 

[thelegion]

(1971 100 hp) After reading this I went outside with the flashlight and checked, and sure as hell my timing advance barely made it past halfway to the rubber stop. Tomorrow it gets rebuilt, this hopefully explains my less than stellar trip out/limp back the other day. Now if I can just find a reasonably priced water pump kit, thats becoming a chore.

thanks for the info F_R

 

[Keyboardman]

Well, checked out the timer base. It's not sticking and gets to full advance before the butterflies start to really open. It doesn't look like anyone's touched the full advance stop screw but maybe I should check the timing? I can't imagine it's the carbs, I did a thorough rebuild, removed all core plugs, jets, soaked them, blew them out, set floats, they are clean as a whistle. This particular engine did have a issue regarding this problem and Johnson sent out a TSB to modify the carbs. I have slightly later model carbs (1978) on it that have the larger SS jets and calibration holes enlarged by the factory. Could still be a carburation prob? This engine runs great at idle and real strong once it gets past the bogging down,,,,,,,,

 

[mrcj001]

When rebuilding the carbs, you have to pay close attention to the needle valve hanger (or spring).....sometimes the hanger gets caught in the float hing assembly and causes a stuck float. If you have a lean condition "blipping" the choke would make it run better.

 

[thelegion]

Well, checked out the timer base. It's not sticking and gets to full advance before the butterflies start to really open. It doesn't look like anyone's touched the full advance stop screw but maybe I should check the timing? I can't imagine it's the carbs, I did a thorough rebuild, removed all core plugs, jets, soaked them, blew them out, set floats, they are clean as a whistle. This particular engine did have a issue regarding this problem and Johnson sent out a TSB to modify the carbs. I have slightly later model carbs (1978) on it that have the larger SS jets and calibration holes enlarged by the factory. Could still be a carburation prob? This engine runs great at idle and real strong once it gets past the bogging down,,,,,,,,

Does anyone know what the procedure was/is? for the carb mod?

 

[Keyboardman]

I have the TSB from Johnson if you need it. Basically replacing the SS jets with bigger ones and enlarging calibration holes.

 

[thelegion]

Quote: [COLOR=#6A6A6A !important]Yesterday, 05:55 PM[/COLOR]


When rebuilding the carbs, you have to pay close attention to the needle valve hanger (or spring).....sometimes the hanger gets caught in the float hing assembly and causes a stuck float. If you have a lean condition "blipping" the choke would make it run better.


Hope this will help (Keyboardman) too.


So I put new kits in the carbs and I included the new hangar (old one never used it) and even putting them back together I can see where they would or could get hung up as that little clip moved around on the float arm allot ; Is there a work around for this??

cheers....

ps. my new carb kit said to make the float even with the new gasket, but I've also read to make it even with the float bowl?