Turning up the Idle

[MiamiU]

hi,

I am new here and was hoping someone could give me some help.

just got a boat with a 1975 85hp on it. I have done a bunch of work to it and it's running really good, but my idle is a little low. From what I have read here it should be about 700rpm in forward gear, it's around 600.

How do I turn the idle up? I am kinda new to outboards, so sorry if this is a dumb question.

Thanks.

 

[Joe Reeves]

Re: Turning up the Idle

It's important to know what compression your engine has on all cylinders (should be 100+ psi & even on all cylinders), and if the spark (with the spark plugs removed) is as it should be.

The spark should jump a 7/16" gap with a strong blue lightning like flame.... a real SNAP!

If the above is as it should be..... There is a idle stop adjustment screw approximately halfway up the vertical throttle lever on the starboard (right) side of the engine. Back that screw away from the stop so that it is not touching.

Loosen the clamp that retains the throttle cable to the engine. Adjust the trunion (threaded knob on the throttle cable) to the proper idle rpm.

On a flushette, the proper rpm would be 1000 rpms. The idle will drop to normal when in the water.

When the idle is where you want it and stays there after applying throttle somewhat and returning the throttle lever to idle..... tighten the throttle cable retaining clamp, then adjust the idle stop screw inward until it hits the stop area.