prop and rpms

[fixin]

I bought a 73' tristar 2400 cruiser with a 351 and merc outdrive.
Theres no way it has the wright prop on it (huge,).Max rpm is 3100 and will run around 25mph(gps).
Can anyone tell me what my max rpm should be?or possibly around what prop I should have.

 

[fixin]

Re: prop and rpms

Sorry can't figure out how to edit....

Boats a Tri-sonic by Roy Rogers not tristar.

 

[Crownie2]

Re: prop and rpms

That's an old one... I'd verify that the tach is correct, first.

But your RPM's should be higher, maybe 4,400.

Is it a Bravo2 drive?? - they have very large diameter props.

Bob

 

[fixin]

Re: prop and rpms

Thanks for the input Bob,

The tac. is close +/- 125rpm.and the outdrive is a mercruiser 888
I know it's the wrong prop because the water diverter thingy (can't think of what you call it)was removed for this prop to fit.
I'm pretty sure the motor is a 302 not a 351.I plan on getting a manual,but computer has some kind of bug that I can't find and I don't trust doing any money transactions till I find out what the prob. is.

 

[Crownie2]

Re: prop and rpms

I guess it's not a B2 if it's an 888 - I don't think they existed then...

Maybe someone with 888 knowledge will respond...

Bob

 

[walleyehed]

Re: prop and rpms

It's just an early Alpha... the diverter thingy is the trim-tab...that doesn't mean the prop is too big, just means you likely need the "correct" trim tab.
As Crownie says, verify the tach.

 

[fixin]

Re: prop and rpms

Again..."The tac. is close +/- 125rpm."and unless the trim tap anode is the size of a pencil eraser...it's the wrong prop.

 

[Crownie2]

Re: prop and rpms

Well - there isn't much doubt - you need to go down in pitch, if you can figure out what is on there now...

Don't worry too much about the trim tab - mine didn't even come with one.

You may have to get close to a dealer or other older boat mechanic.

Good Luck

Bob

 

[walleyehed]

Re: prop and rpms

+/- 125RPM is not a very close-to-accurate tach.
This is a major problem that few will take care of, yet want outstanding performance.
All perameters of prop set-up are references of an accurate tach...+/- 125RPM is 1-2" of pitch..
And....the proper trim tab extends to the rear, and in no way interferes with blade travel...possibly we're talking about something else...

 

[dodge1971340]

Re: prop and rpms

Hi d the (WOT) should be 4400 to 4600 for the 302 that old but being that old i would keep it around 4400rpms max ,,,Good luck. Dodge