Needs Prop help on 1997 Evinrude 25 with low MPH

[asianstars]

1st time boat owner needs some helps.... Just test run the boat with 2 persons onboard and found boat did not have enough speed with high RPM. The engine is making high RPM, but not pushing hard enough. Read several article about changing to higher pitch or increase diameter of the prop. What is the ideal prop size to maximize the engine size?

Current prop is a 3 blades AL with a marking of 10x13

The engine is 1997 Evinrude 25 E25ELEUB 2 strokes. Per spec., gear ratio is 2.15:1, Min WOT RPM 4500 and Max WOT RPM 5500

My boat is a 1997 Carolina Skiff J16 flat bottom fishing boat.

Hope to get some help on a ideal prop size that can give the engine a optimal push. Thanks!

 

[hwsiii]

Re: Needs Prop help on 1997 Evinrude 25 with low MPH

Asianstars, I show a total boat weight of about 1,100 pounds with two people on board and other sundry items. The prop you need is an aluminum 13" PITCH AND YOU SHOULD RUN ABOUT 26 MPH, and that is what you have now. Here are my program numbers. But you do need to purchase a Tiny Tach for about $ 40 to KNOW what your RPM are.

Prop Picker

H

 

[steelespike]

Re: Needs Prop help on 1997 Evinrude 25 with low MPH

Welcom,Good job on the info.
Your setup appears to be right.I suspect a motor issue.
May be running on one cylinder. Pull and ground one plug wire at a time.
see if it will run.
Or pull the plugs and see if one is fouled or wet with gas.
Check that the throttle is opening all the way.
Your actual rpm and speed will help determine whats up.Unfortunately
"not pushing hard enough" isn't enough info.
The Tinytach suggested is easy to install and will work on any 2 cylinder,2 stroke motor without regard to stator poles.A borrowed gps is excellent for speed.

 

[asianstars]

Re: Needs Prop help on 1997 Evinrude 25 with low MPH

Thanks for the information. I will test run again using GPS to measure the speed and get Tiny Tach for the RPM.

From my reading, a 10x13 prop can get me ~22-28 MPH and a 10x15 prop can get me ~25-33MPH. Or these information are all relative until I get the RPM reading right. Thanks!