1991 johnson 8hp idle adjustement

[morenc00]

My outboard is running a little bit too fast at idle, how I sould adjust the linkage to reduce the speed ? by unbolting the throttle cable bracket from the cylinder and rotating it a couple of turns?

also how should I adjust the idle mixture (top screw on the left side of the carb) right now it's at 2 1/4 turn from bottom which happend to be about 1 turn back from when it start shudder.

this outboard will be used as a kicker only for trolling at slow speed

thanks for the help

 

[morenc00]

Re: 1991 johnson 8hp idle adjustement

anyone can help me ?

 

[tashasdaddy]

Re: 1991 johnson 8hp idle adjustement

you have to give us time to answer.

(Carburetor Adjustment - Single S/S Adjustable Needle Valve)
(J. Reeves)

Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.

Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.

Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

Note: As a final double check setting of the slow speed valve(s), if the engine has more than one carburetor, do not attempt to gradually adjust all of the valves/carburetors at the same time. Do one at a time until you hit the above response (die out or spit back), then go on to the next valve/carburetor. It may be necessary to back out "all" of the slow speed adjustable needle valves 1/8 turn before doing this final adjustment due to the fact that one of the valves might be initially set ever so slightly lean.

When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.

 

[Vic.S]

Re: 1991 johnson 8hp idle adjustement

The knob on the end of the tiller is the idle speed adjustment.

The (roughly) horizontal screw on the top, front, port side corner of the carb top cover is the idle mixture adjust. Basically adjust for best running at idle speed but slow that down first.

There is a post on the Engine FAQs board on carb adjustment. q.v. But Tashasdaddy has beaten me to it by copying the relevant bit.