78 Evinrude 85hp ignition timing.

[Ships n' Giggles]

Hello all! I'm new to working on outboards. I bought my first bass boat with a 78 Evinrude 85hp. I've done a bit of work on it but now I'd like to get it tuned. When I start the motor it idles pretty high. I've been told to check to ignition timing. Does anyone have any tips on how to do this? Any info will be greatly appreciated! Thanks

 

[joereeves]

Forget the timing for now. The idle rpm, if running on a garden hose (a flushette) would be 1000 rpm. "Pretty high" means nothing to us... how high is the engine running at present (rpms?)

The first thing to so is to remove all spark plugs and check the compression. What is the individual compression psi readings of all cylinders. The cylinders are number as standing in back of the engine, facing the spark plug area.....

2.....1
4.....3

The second thing to do is to check the spark (S/plugs still out) which should jump a 7/16" gap on all cylinders with a strong blue lightning like flame... a real SNAP!... Does it?

Let us know what you find.

 

[fdrgator]

The ignition timing procedure relates to wide open throttle timing. As Joe said, leave it alone unless you have a valid reason to mess with it.

Idle speed relates to several adjustments. And yes, primarily controlled by timing (spark retard). But that advance/retard changes every time you move the throttle control. Moving the control to slowest position sets the retard to whatever the idle speed setting is. Summing up to what I'm stumbling around saying is set the idle speed and/or control cable to desired RPM and don't be worrying about slow speed timing.

If it really is out of whack due to tampering, you will need to do what is called a link and sync. You need a manual and go by the complete procedure to do that.