4.3 merc with low wot

[jam1ej20]

I have a 1995 mercruiser 4.3 with the alpha 1 gen II drive in a V19 Dixie ski boat. WOT is just over 4000rpm and top speed with average load is just over 40mph(gauge). The prop doesn't have a lot of markings or numbers on it, but what i can make out looks like a 15x23.

-Does this prop dimension sound right?

-If this is the actual prop dimensions, what was the goal? (better hole shot? etc.)

-What is normal WOT for this motor and could this prop be affecting this?

I have not had a skier behind the boat yet to determine pulling power and I am fine with 40mph top speed. I am more concerned with pulling power and being able to pull watersports toys with ease. Please advise.

Thanks!

 

[junior1113]

Re: 4.3 merc with low wot

wot rpm recomendations for this motor is 4200- 4600 the closer to 4600 the better. yes u r lugging your motor right now and hole shots are suffering because of it. going down in pitch will raise rpms. 23 is prop pretty high for this application. id look for a 3 blade 20" pitch or if you really want awsome hole shots i would reccomend stepping up to the 4 blade 19" pitch. ill never buy another 3 blade,4's can plane faster, better fuel econ., better handeling, slower plane speeds(great for watersports), better in handling heavy loads at slower speeds, and even pick up top end in most cases. first verify that prop you are running is indeed a 23" pitch. is it ss or alluminum?

 

[jam1ej20]

Re: 4.3 merc with low wot

The prop is SS. What would be goal of a 23"pitch prop on this boat? Any idea?

 

[junior1113]

Re: 4.3 merc with low wot

people think they can put any pitch they want to get speed when in fact the if the rpms are'nt high enough performance will be affected.
i would assume someone that didnt know much about motors or props put it on thinking it will be faster.

if you get the rpms within range your performance will be great besides max hp is rated at 4400-4500 so u only have 90% instead of100%

could be a lot of reasons why its on there. if there was 1 75lb guy in it with 1 gal. gas and thats it. this prop might work

the most important thing about a prop is that it meets recomended rpms for overall performance and motor life. very important