Re: air cover on ’68 Johnson 20hp – needed?

[johnyrude200]

At idle, it needed 1.25 turns out to 1.5 turns. The initial calibration settings call for 1 turn out, which it runs great at from mid to top end. But at idle, it stalls out and spits back. Basically adjusting the carb back and forth has it running really well (no air cover). Makes sense about more air at mid to high range having affect with the air cover. This very well could have to do with the cold running condition (I think the highest it reached was about 115-120° even at mid throttle).

The timing was set as far out as it could on the follower cam and the pickup was basically between the two setting marks. What I have noticed is the linkages on these motors are pretty sloppy; even with tight brass fittings and metal linkages (the ones that basically look like bent fence wire), there is some play. It is not only at the linkages, but also at the throttle assembly articulation which connects to the stator arm (the one that is brass, which rotates the magneto plate). I also notice on these 20hp motors that follower cam really doesn’t do much in terms of opening up the carb flap until the top end, I saw basically no opening of the carb flap for at least 1/2 of the time the follower was rolling on the cam.

I think it’s splitting hairs at this point, because with this much ‘slop,’ there’s only so much that can be done IMO.