Lack of top end power

[63 Evinrude]

My Evinrude 63 18hp is really running good now thanks to the help of a lot of people on this site. I how ever have a nagging problem. I’ve had the motor out several times and it seams that the motor will not reach top end. When in neutral the motor will really revs up high but when in forward it just doesn’t sound like it is getting the max rpm. The motor runs strong but I can tell it still has some more to give. I have tried several different point settings and it seams that a setting of about the thickness of a credit card works the best. All tips or suggestions will be very much appreciated.

 

[rickdb1boat]

Re: Lack of top end power

All I can tell you is the points should be set at .020. This directly affects the timing and may be your problem. Are you sure your throttle flap is opening completly? Choke wide open? Plugs gapped right. Propped right? Just a few ideas... What kind of boat is it on and the length?

 

[63 Evinrude]

Re: Lack of top end power

I checked the cam follower it’s opening the carb all the way. I was thinking about using a hotter plug a B7S NGK but I’d have to order them. I’ll try the points again. I have a little fiberglass john boat it’s about 300 maybe 400 Lbs I just flipped it over my self to wax the bottom so it can’t be to heavy.

 

[rickdb1boat]

Re: Lack of top end power

Should be running a 9 1/4 X 11 or 9 1/4 X 12 prop for best top end.

 

[63 Evinrude]

Re: Lack of top end power

Thanks I'll look at the one that came with the motor. Is there an easy way for me to tell what type I have now?

 

[Paul Moir]

Re: Lack of top end power

Using a hotter plug won't help your top end, just your low speed fouling. At high speeds, all you can expect to gain from a hot plug is a holed piston.<br />Use a Champion J4C, gapped at .030. They work better in these engines than an NGK. I know, I know; I have no fondness for Champions either, in any other application.<br />Also reving the engine in neutral is a quick way of destroying it. It will run away, especially with a hot plug! When that happens, you can expect tossed rod or a liberated flywheel. Never ever operate these engines above 1500rpm without a load!

 

[63 Evinrude]

Re: Lack of top end power

thank you for your advice Paul. I'll try the champion plugs, and keep the rpm's low in neutral.