Classic case on a 1967 Johnson 20hp

[restornator]

This problem is a classic on here but i never really paid attention to them. motor runs sluggish at the highest idle. When i pull the choke halfway out, it revs up, and i can decrease the throttle as long as i am holding the choke. Basically it runs like it is supposed to with half choke

Sounds like an air leak in the fuel delivery system, so where do i start? the previous owner had the same problem, he just didn't know it. i am not using his tank and hose.

 

[kbait]

Re: Classic case on a 1967 Johnson 20hp

If you pump the bulb and it still acts up, it's inside the carb. You may have faulty hose connections yet, but once you get a bowlful of fuel, it shouldn't act like that. Dismantle and clean carb/passages, and make sure float is set correctly.. Good luck!

 

[F_R]

Re: Classic case on a 1967 Johnson 20hp

It is supposed to speed up when you pull the choke out a bit. That is because there in an interlink between the choke and throttle butterflys.

Exactly what is the problem? Runs sluggish at high idle(??) Does it run ok at other speeds? Have you tried adjusting the idle needle? The synchronization may be off too.

 

[restornator]

Re: Classic case on a 1967 Johnson 20hp

It is supposed to speed up when you pull the choke out a bit. That is because there in an interlink between the choke and throttle butterflys.

Exactly what is the problem? Runs sluggish at high idle(??) Does it run ok at other speeds? Have you tried adjusting the idle needle? The synchronization may be off too.

lol duh, i forgot about that. well that makes some sense then. It was weird when i pulled the choke out a bit, because it just about doubled its speed. The choke makes it run richer by reducing air intake, right? the only way i know how to sync it is when the mark on the throttle cam reaches the cam follower, the throttle should begin to open up. Remember in this year, the throttle cam restricted fuel until it reached the upper end of the cam movement? The timing mark on this cam is at about the middle of the cam length

 

[restornator]

Re: Classic case on a 1967 Johnson 20hp

turned out to be no spark on cylinder 2. I took the flywheel off and the coils looked fresh. Could be the anchor pin where the plug wire goes is corroded. But how would i set the points? there is no access port on the flywheel, just a couple small holes