Evinrude 1981 9.9 stuttering help

[soup1279]

I have a 1981 Evinrude 9.9 model E10RCID outboard I'm having some trouble with.

It starts just fine and stays idling just fine however under load it seems to only run on one cylinder. When the throttle is wide open it gets very jerky and you can feel/hear the other cyl kick in then shut off then kick in etc. Making the ride very jerky. Also when you let off the throttle from Wide open throttle, even just a little bit it just goes right back to idle regardless of where the throttle position is. I then have to turn the handle down to idle speed in order to 'reset' itself so to speak. When I do that it runs just fine and I can increase speed enough to get up stream... slowly... If i try to get on plane again the same thing happens.

It idles fine and putts up the river fine but when I want to get on plane it gives me the issues listed above.

Is there a chance the ignition module could be the culprit? or Would that happen at all times not just under load?

The plugs are new, I had the plugs out and tested by cranking I was getting spark on both. The carb is clean and has all new parts. It's not over heating and again it starts up first time every time w/o issue and stays idling w/o issue.

Any idea?

Thanks,
Anthony

[Rick.]

These motors run exceptionally smooth on just one cylinder. The issue of running on one only normally shows as a general lack of power at a higher throttle position. I would suggest you get a spark gap tester and check for good spark jumping 3/8ths of an inch. Spark should be blue/white and snappy. You need to have a really good look at your link and sync regarding "goes back to idle" when you let off on the throttle. It seems to me something is not aligned or is slipping the throttle to carb. throttle plate is all mechanical. I've not experienced what you've described. A service manual is very necessary if you don't already have one. Best of luck. Rick.

[Haffiman]

And the compression readings are?

[ondarvr]

Check the coils for cracks. They can work at low speed, but as the RPMs and load increase they can short out.

[soup1279]

These motors run exceptionally smooth on just one cylinder. The issue of running on one only normally shows as a general lack of power at a higher throttle position. I would suggest you get a spark gap tester and check for good spark jumping 3/8ths of an inch. Spark should be blue/white and snappy. You need to have a really good look at your link and sync regarding "goes back to idle" when you let off on the throttle. It seems to me something is not aligned or is slipping the throttle to carb. throttle plate is all mechanical. I've not experienced what you've described. A service manual is very necessary if you don't already have one. Best of luck. Rick.

Thanks i'll look into that. I'll also look into finding a service manual.

And the compression readings are?

I'm not sure as I don't have a gauge to test them.

Check the coils for cracks. They can work at low speed, but as the RPMs and load increase they can short out.

I'll check this as well.

Thanks

[sutor623]

Well I have worked on a few John/Rudes of this era. The ignition systems are nice, but hard to troubleshoot. Really, the CDI Manual is the only way to pinpoint the issues. I have seen more then one Timing sensor assembly go bad. They are facing the back of the motor, under the flywheel. OMC had the same ignition system from 4hp to 60hp, and for almost 30 years, there is a reason for this. http://www.cdielectronics.com/downlo...04-60%20HP.pdf