Timing advances too far and running rich

[glengold]

1977 55hp evinrude - I'm expecting to get more power out of this motor, trying to figure out what is causing my problems. Compression checks out OK 145/140. This weekend I took the timing light with me to check WOT timing. This motor needs 19 degrees WOT and it's going all the way to 22~23. The notch in the adjustment was broken off and I couldn't adjust it with pliers so we just fished the rest of the day and I'm letting is soak with some PB blaster this week so I can adjust it.

Now another discovery I made while checking the WOT timing is that the motor runs about 600 rpm higher with the cowling off, right up to the max RPM of 6 grand. My thoughts are that the motor is running rich with the cover on, so the added air flow of the cover off leans it out to where it should be. Could the improper timing setting be causing the motor to run rich? If not how can I adjust for the rich running? Been in the carbs half a dozen times, floats are slightly off level. Should I try making them more off level?

I can't wait to adjust this timing and see how she runs at the proper setting, what do you think 3-4 degrees will do to performance? I've always thought advancing too far would kill the motor.

Thanks-
Glen

 

[gransee]

Re: Timing advances too far and running rich

I am having a problem with my motor running to rich also. Mine is a 1975 johnson 25 hp. Seems to flood out after running for a while. If you figure out what is wrong with yours, please share. Thanks.

 

[Haffiman]

Re: Timing advances too far and running rich

On engines that loose power with cover on, the reason is normally an exhaust leak from somewhere.

 

[glengold]

Re: Timing advances too far and running rich

I have heard it might be an exhaust leak, but wouldn't i see exhaust when i pull off the cowl? This isn't the case.

 

[Haffiman]

Re: Timing advances too far and running rich

Not necessarily. The concentration built up under the cover might be 'diluted' when removing the cover. Normal places are base gasket ( power head/exhaust collector, exhaust cover).

 

[glengold]

Re: Timing advances too far and running rich

Timing has no effect on mixture? I'd think if the spark wasn't timed right it may not be burning all of the fuel. What does an extra few degrees do to performance? After doing some research last night I know that I need to determine if TDC lines up with the pointer before I start adjusting the stop.

As for the exhaust leak, if I can't see it how do I test for it?

 

[Haffiman]

Re: Timing advances too far and running rich

There are a couple of ways that normally work.
But try taking a soap mix in a spray bottle ans spray on all areas where exhaust may leak. Any bubbles and you have a leak. If the big rubber seal is leaking or missing between gear case and leg, it might even get up with the shift rod.