25 evinrude cutting out at wot

[JohnnyO3]

My ‘95 25hp evinrude starts, idles, trolls perfectly. At wot it runs great for a few minutes then it’s like one cyl cuts out. Shakes violently and won’t speed up. It may clear up for a bit and do it again. Sometimes revving it in neutral or shutting off and restarting clears it up briefly. New impeller as I thought it was slow mode. New powerpak and coils let year

 

[racerone]

What boat ?---What prop ?-----Perhaps hitting the rev limiter if powerpack has that feature?------I can not see or hear your motor.

 

[JohnnyO3]

No it doesn’t go away if I slow down so not a limiter

 

[rowerowe101]

Sounds like a fuel restriction, maybe needle sticking or something similar if it's carbuerated.

 

[rowerowe101]

you've compression and spark tested?

 

[JohnnyO3]

As previously mentioned it doesn’t go away when slowing down so it’s not fuel starvation.

 

[JohnnyO3]

Bottom cyl is fouling at wot... clears up briefly if I shut it off and restart.

 

[oldboat1]

I would want to see if it's losing spark on the lower cylinder at WOT, or thereabouts. You might hook up a timing light to see -- no flash, no spark.

Also, check the prop. Make sure the prop nut is locked down and the spacer is in place.

 

[werewolf]

mine was plug wires , 25 johnson thinks its a 50 now ha