85 johnson 150 not wanting to stay running in gear

[james95gt]

finally, got my boat on water today. it starts up fine, idles great the only problem is when i put it in gear to go foward it wants to run rough and wants to die on me. will not let me give it barley any throttle. but will start right back up... could this be a timing issue for the engine to to run like this???
fuel lines all checked and carbs all rebuilt and clean gas properly mixd
any help would be appreciated

 

[jonesg]

Re: 85 johnson 150 not wanting to stay running in gear

Feel the cyl heads to see if its firing on all holes.
A spark test or a timing light would help to check for ignition.
Also have someone pump the bulb as you put it in gear, could be a weak pump.

 

[emdsapmgr]

Re: 85 johnson 150 not wanting to stay running in gear

Make sure the idle is high enough so it won't die when it goes into gear. Should be set between 650-750 rpm, when the engine is idling in gear, floating normally in the lake. The idle rpm's are not set through the carbs, but by adjusting the idle timing in the ignition system. If it still wants to die, it is possible you may have some restrictions in the idle circuits in the carb bodies. You may need to tear them down and blow them out with some aerosol carb cleaner, then reassemble. Do you get any sneezing (apparrent misfire) at idle at all?

 

[james95gt]

Re: 85 johnson 150 not wanting to stay running in gear

im getting spark on all cyclinders, it idles great but when i go ahead and put it in gear it it bougs down and shuts off. got even compression on all cyclinders my my primer bulb is always hard and getting fuel pressure, the only reason im thinking its timing is my buddy thought he knew what he was doing and adjusted the idle screw to raise the idle but i think it was the timing advance screw. but im not sure

 

[emdsapmgr]

Re: 85 johnson 150 not wanting to stay running in gear

The screw on the spark advance lever is the correct one to adjust for increasing the idle rpm. If the idle rpm is set to spec, it is still possible that one or more of the idle passages in the carbs are restricted and won't supply the fuel required to maintain proper idle when under load.