14.5x19 prop. Contemplating a change, need advice

[rhedayi]

Hi gang
Boat is a 96 bayliner trophy 2002 cuddy cabin
Engine was a force 120. Repowered to 2016 Mercury 4 stroke 150. Currently the prop is merc aluminun 14.5by 19. Wot is 4800 rpm and i find myself cruising at 25mph at about 3500 rpms. My fuel efficiency according to smartcraft gauge is 6.1gph at that speed.

I feel like perhaps I’m too low in terms of rpms. Hole shot seems sluggish but way better than the force.
I have a Michigan wheel 15x17 aluminum prop. Is it advisable to change to that ACS what should i expect ?

 

[jimmbo]

First of all, what is the WOT Range for that Engine?
Is is the Engine in Good Mechanical Condition and in Tune?

About 5200 rpm, which is still likely on the low side

 

[rhedayi]

It’s wot range is 5000-5750. I would say it’s in great mechanical shape.

 

[jimmbo]

Dropping to a 15 inch will get you closer to the 5750

Have you done a Compression Test on the Engine?
Is the Spark strong enough on all Cylinders to jump a 3/8" Gap?

 

[airshot]

Right now you stated the wot is at 4800 rpm, so your lugging your engine and making it work harder. With a light load, I would adjust your pitch to get you near the max wot your engine is rated for. Cruising speed/ rpm mean nothing, wot rpm is what you prop for.

 

[cyclops222]

Motor is still on ....baby it... Break in time ?

 

[jlh3rd]

since you already have the Michigan wheel, try it. It's free, and at least it will help you decide what prop you might need to get.
You're 1000 rpm's low @ WOT.
yep, your lugging.....and is the motor healthy.