1988 4.3L OMC with 14.5 x 19p prop top speed/RPM at WOT?

My 1988 4.3L OMC with 14.5x19p prop top RPM is 4000 at 35MPH max. Does this look correct? The motor is a fresh rebuild long block with new pistons, rings, rods, etc. The timing indicate 6 BTDC and I'm running 87 octane gas, boat location is Houston, TX. I've watch videos in youtube, the boats with similar engine top speed is over 40-50 MPH.

OMC Manual stated 4.3L WOT should be 4200-4600 RPM.


Does this prop has anything to do with it?

Re: 1988 4.3L OMC with 14.5 x 19p prop top speed/RPM at WOT?

Um...

Yes, that prop is a serious problem. All that $ on engine work, to have it strain trying to spin that turd? :facepalm:

It's so bad, my initial reaction was, "This guy is a comedian."

I am being blunt to drive home a point. Get a new prop, and it should be a 19p like you have there. I'd get two, and both should be alum, because you have a proficiency for smacking innocent rocks around.

My only caveat is that you should try a 19p that is clean and fresh and ensure it does what it should with that newer engine: Spin it up to upper RPM range. There's a slight chance you need a 21p, but it is likely you should just get a fresh 19p and you can then zoom around at 45 MPH knowing you aren't trying to bend the new con rods in your fresh engine.

Re: 1988 4.3L OMC with 14.5 x 19p prop top speed/RPM at WOT?

Philster said:

Um...

Yes, that prop is a serious problem. All that $ on engine work, to have it strain trying to spin that turd? :facepalm:

It's so bad, my initial reaction was, "This guy is a comedian."

I am being blunt to drive home a point. Get a new prop, and it should be a 19p like you have there. I'd get two, and both should be alum, because you have a proficiency for smacking innocent rocks around.

My only caveat is that you should try a 19p that is clean and fresh and ensure it does what it should with that newer engine: Spin it up to upper RPM range. There's a slight chance you need a 21p, but it is likely you should just get a fresh 19p and you can then zoom around at 45 MPH knowing you aren't trying to bend the new con rods in your fresh engine.

Click to expand...

Ayuh,.... It's Amazin' the effort folks put into their Motor, 'n then run a wheel like That...