more rpm and speed

[Randy Jones]

I have an 88 Evinrude 150 that runs about 56mph @ 4900rpm . It seems it should run faster. My prop is 14 1/2" x 22 . Can I raise the motor on the jackplate or do I need a new prop.

 

[Jack Shellac]

Re: more rpm and speed

Welcome to the forum. The best thing for the long-term health of your motor is to prop it so that turns in the upper part of the recommeded RPM range at WOT. If you run it below, you're lugging the motor, which is definitely not good for it. It sounds like you may already be over-pitched at 4900RPM [if the range is 4500-5500 RPM like I seem to remember]. A jackplate may or may not help. Some of the other guys may have more specific opinions.

 

[Dhadley]

Re: more rpm and speed

Just guessing from the info you gave -- yes raising would probably help. Since you already have a jackplate its real easy to test. Again, guessing it would seem you have a Raker prop but we need to know. Tell us a litle about the hull. Since it has a jackplate and a fairly healthy pitch we're guessing its a pad bottom hull.<br /><br />Make sure the motor is running as it should. No sense chasing a set up problem if the motor isnt running up to spec.<br /><br />When you say "about" 56 mph - find out exactly what speed you are running. 56 at 4900 is almost 0% slip. <br /><br />Watch your water pressure and have fun. Let us know how you make out.<br /><br />Good luck!

 

[Randy Jones]

Re: more rpm and speed

Yes , it is a Raker prop, as far as the hull, all I know is that the boat is a Procraft bass boat 17' 8" lenght . The motor runs great.