96 evinrude 20 hp runs rough mid range

[Skiptrace]

This is an ongoing problem. Since I either troll or run it on a plane (80-85% throttle it's livable but vexing. At idle and a short amount above that it runs smooth. When I open it up anything less than say 75% I seem to lose one cylinder. I have rebuilt the carb,changed the leaf valve, replaced the plugs and wires. Nothing has changed although I did fix some other issues I was more concerned about. I bought it used and have had it 5 years. Oh one other thing probably not related but.. it needs a new stator. I charge the battery manually when I get home and it never runs down when I use it. What is likely the next step?

 

[racerone]

post the results of a compression test.

 

[saltchuckmatt]

"needs a new stator. I charge the battery manually when I get home and it never runs down when I use it. What is likely the next step?"

This line makes no sense. If you have a charging issue check the rectifier.

Besides checking compression (do this first) try a different carb.....this assumes you've cleaned/rebuilt the carb correctly.

I have my doubts.

 

[jimmbo]

That Motor does not Need a Battery to Run.
When you rebuilt the Carb, did you make sure to check and adjust, if Necessary, the Sync between the Carb and Ignition Advance?
Again to the Carb, When you "Cleaned it", did that include removing the Disc Plugs and cleaning the Areas behind them? Did you set the Float Correctly? Did you install the Gasket, for the Main Nozzle, if it wasn't part of the Bowl Gasket?

 

[Skiptrace]

Compression 100 both cylinders cold 105 warm. most of the work on the carb was 4 years ago. There was no change after except I fixed the worst problem which was vaporlocking when warm. Was probably fuel line as it resolved after addressing connections.That is not an issue anymore but everything remains the same. I did the carb following a video from danger Marine and he did a detailed explanation on the 30 which is identical in most regards to the 20. Could I have done it wrong? Sure, so that's a possibility. Regarding the rectifier it checks good and the stator measurements are off. And the motor may run without a battery, but it won't start. And thanks to all who are chipping in. I obviously can use all the help I can get.

 

[saltchuckmatt]

Compression is basically no good....not worth doing anything.

4 years ago is a long time.

Running the motor not hooked up to the battery ruins the rectifier but I guess your never ran that way.

Time for a parts motor with a good power head.