Evinrude 70hp rough at full throttle

[Jeff P]

Evinrude 70hp Model #E70TLEDR runs fine until full throttle then acts as if it wants to come apart. When I let off the throttle just a little bit, it runs smooth. Idle is great, if this is a needle valve adjustment...how do I set it correctly at full throttle?

Thanks,
Jeff

 

[tashasdaddy]

Re: Evinrude 70hp rough at full throttle

while not running, remove the air silencer from in front of the carbs, have someone advance the throttle lever to full throttle, the butterfly plates in the carb should be level, no tilt up or down. it sounds like the throttle linkage is moving the butterflies, too far, and they are tilting too far, causing the gas air mixture to be too high. this would then be a link n sinc problem, link n sinc is covered in your OEM Evinrude manual.

 

[Jeff P]

Re: Evinrude 70hp rough at full throttle

while not running, remove the air silencer from in front of the carbs, have someone advance the throttle lever to full throttle, the butterfly plates in the carb should be level, no tilt up or down. it sounds like the throttle linkage is moving the butterflies, too far, and they are tilting too far, causing the gas air mixture to be too high. this would then be a link n sinc problem, link n sinc is covered in your OEM Evinrude manual.

That doesn't seem to be the problem because at full throttle the butterfly plates are level. Is there anything else I can look for?

 

[tashasdaddy]

Re: Evinrude 70hp rough at full throttle

what do you mean it wants to come apart? better description. what have you checked.

 

[Jeff P]

Re: Evinrude 70hp rough at full throttle

what do you mean it wants to come apart? better description. what have you checked.

It runs as if it is getting too much air, a lean mix. The butterfly plates were the first things I checked, but that doesn't seem to be the problem. They are level a WOT. It feels like someone is tapping the kill switch at WOT, but why would it act like that only at WOT and not anywhere else in the throttle range?

I appreciate every effort of help.

Thanks,
Jeff P

 

[tashasdaddy]

Re: Evinrude 70hp rough at full throttle

i think we need to start are the basics, a compression and spark check. it also could be a loose or corroded connection. that is shorting out the power pack or the coils. also check for any fuel restriction, leaking hose, clogging fuel pick up in tank.

are you sure you are not close to running hot, could be the temp sensor, trying to throw it into slow mode. i'm really grasping at straws here.