wondering about props you folks are on with a 1991 4.3L 18 ft boat IB/OB

[boaterinsd]

my setup now is as follows:
14.5" x 19 deg 3 blade prop
1.68 ratio overall in outdrive
4.3 L OMC cobra motor
4200 RPM
and 40 MPh
No trim tabs and or hydofoil on the boat. Problem i am having is excessive time to get on plane, like 5-10 sec with 1 adult and to kids on board. On the 4th we had a full load 8 people and we to 5 times longer to achieve it. I wanna be up and on plane a lot sooner that those times. Next time out i am gonna check for a spun hub also. Do i try 4 blade prop or what? Please any help or info would be great....

 

[steelespike]

Re: wondering about props you folks are on with a 1991 4.3L 18 ft boat IB/OB

Prop size is in inches allways listed diameer X pitch.
I think a 4.3 in a lightly loaded 18' boat should turn up a 21 or 23" prop to about 4800 rpm and around 50 mph.
Your boat should leap up with a 19" prop. and over rev at wot.
Hopefully the motor is just out of tune.If you want quicker hole shot trim tabs or smart tabs will help.
Applied carefully with just enough pressure to be effective.

 

[boaterinsd]

Re: wondering about props you folks are on with a 1991 4.3L 18 ft boat IB/OB

i whould think so too. I am gonna try a different prop and see what happens. Then ck on original for slipping( spun)condition. will advise.

 

[jestor68]

Re: wondering about props you folks are on with a 1991 4.3L 18 ft boat IB/OB

I don't know why folks are surprised when a 22 year old motor can't pull the pitch it used to.

A 17 pitch will help your tired motor regain some of it's get up and go. :joyous: