1979 Johnson High Idle 85 HP

[oklakerat]

I have read numerous postings regarding high idle, and have attempted the various fixes (checked plates, air leak, linkage adjustments, etc) with no luck. I idle at 1200 rpm in neutral and 1000 rpm under low load on a 35 foot houseboat. I fear the constant shifting at high rpm will damage the gears.<br /><br />When I move the timing advance by pushing aft on the throttle linkage when in neutral, I can achieve 750 rpm, but the tension spring bounces the advance forward when I release, going back to 1200 rpm. I called a local shop and they suggested adjusting the timing, due to adjustment of the spring and/or angle of the advancement arm is not feasible. I also read a post that suggested changing the size of the low speed jets.<br /><br />Any advice on these suggestions or other solutions? If I can adjust timing, which way should the adjustment be made?

 

[Dhadley]

Re: 1979 Johnson High Idle 85 HP

I may not understand the question so stick with me. If you can get the correct idle rpm by pushing back on the timer base, that means the throttle cable is not pulling the throttle arm back so the stop screw is hitting.<br /><br />Remove the throttle cable and pull the arm back to get your correct idle. Then recenter your cable.<br /><br />Good luck!

 

[oklakerat]

Re: 1979 Johnson High Idle 85 HP

Maybe I do not understand.<br /><br />We haven't been able to position the throttle cable in such a way as to pull the throttle arm any more forward than is manually possible. But perhaps we are missing something.<br /><br />I can remove the throttle cable and pull the throttle arm forward as far as it will go (which I believe is limited by the carb plates being all the way closed, correct?), and the timer base will still not move backward (aft) due to the tension from the spring that the timer base arm is connected to. Are you saying that there is a way to readjust the angle of the (what I will call) throttle arm versus the timer base arm such that the spring has less effect. I have backed the stop screw all the way out, but it makes no difference, because the spring will push the timer arm forward at least half an inch, so that the stop screw is irrelevant. That is when my rpm's hit 1200, and when I manually push it back to the stop (which is all the way out), I can get in the 750 range.