89 johnson 20 horse

[curt edwards]

I have a 89 johnson 20 horse motor that starts great 2 pulls, idle's fine,and i can run up and down the lake full throttle. This motor runs great, the only time i have a problem is if I let the motor idle for a couple minute,s or do a slow troll, when I take off it starts cutting out at about third of throttle. The last time it did it I shut down the engine stated it back up,one pull and it ran great again. anyone know what the problem could be? If i was on a small lake i could live with the problem, but if on a large lake a ways from boat landing after trolling i don't want to be messing with the motor. Please help!

 

[tashasdaddy]

Re: 89 johnson 20 horse

moving to Johnson forum, open you spark gap to .035 or .040 if you do a lot of trolling. you also have an adjustable slow speed air mixture screw, could be too rich. see TOP SECRET FILE.

 

[curt edwards]

Re: 89 johnson 20 horse

dumb ? is that the screw on the top left of carb and which way do i turn it

 

[tashasdaddy]

Re: 89 johnson 20 horse

it is an experiment, until it idles it's smoothly. 1/8 of a turn, wait 15 seconds.

 

[curt edwards]

Re: 89 johnson 20 horse

it idle's smooth, that's not the problem. it's when I tromp on it it goes conk, conk conk shut it off start it and it runs great again. thought i would just adjust that screw a little bit don't know which way to turn it. It runs to good to mess with it too much. is that scew on the top left of carb the one and which way do I turn it

 

[tashasdaddy]

Re: 89 johnson 20 horse

carb kit, sounds like the high speed jet is clogged partially, and you may need a link n sinc.