Prop Change

[Jeep Man]

I finally got my newer boat in the water. I think I need a prop change. It's an '08 Sun Tracker 20' pontoon with a 60 hp Merc Bigfoot. My new tach isn't hooked up yet but I had a Merc mechanic sort out some minor problems (filter, scan etc.)and he told me it now runs 19.8 mph at 4900 rpm at WOT. The prop is a 14x11p. RPMs should be near 6000.
What prop should I change to?
Am I hurting the motor at this WOT RPM?
How will top speed be affected with different prop which will allow better RPM?
14x9 has been suggested. Is this the right one?

 

[hwsiii]

Re: Prop Change

Jeep, it is detrimental to the motor to run at that low an RPM and your prop slip is good at 11% for that type of vessel. A 9" pitch in the exact same make and model of prop you are running right now will be perfect and I do not believe you will lose any speed. Here are the numbers.

Prop Change

After you run the new prop please come back and give me the new WOT RPM and speed for my database.



H