newbie prop help

[rau]

newbie prop help

1st time owner.previous owner had engine replaced
(3.0L 140HP)Has older pre-alpha out drive(1977).On prop J14.5X 19P.Mechanic told last owner prop needs
to be replaced.At low end of RPM (4200-4600) at WOT.
Which it is.Just looking for less stress on mechanicals.
Any suggestions?Thanks

 

[walleyehed]

Re: newbie prop help

Re: newbie prop help

Yes, it's best to prop close to the top of the Range with a normal load...
Can you get a P/N off of the prop?
Do you want to stay with aluminum or do you wish to gain some performance?

 

[rau]

Re: newbie prop help

Re: newbie prop help

[]

Number looks like 48 8328 30A45 19P
Aluminum is ok
Just looking to get to proper RPM
Thanks again

 

[walleyehed]

Re: newbie prop help

Re: newbie prop help

That is a Black Max 15-1/2X19, un-cupped aluminum prop..Usually when going from un-cupped to cupped the 2" drop in pitch doesn't add much more than 150-200RPM at best, but I think a 15P cupped would be too low of pitch. Take a look at this link...I think this is what you'll be looking at in aluminum. Just left-click on link below.

http://www.iboats.com/mall/propfind...id=475&session_id=932573050&cart_id=733937387

 

[rau]

Re: newbie prop help

Re: newbie prop help

Don't understand. How could it be a 15 1/2 x19?
When on the prop it says J141/2 x 19P?
Maybe wrong part #
Thanks for your help.

 

[walleyehed]

Re: newbie prop help

Re: newbie prop help

According to the P/N you give, My Merc book says 15-1/2X19, and still available...
There is a chance a prop shop could have cut it down and stamped the new diameter into it.
Possibly trying to get some higher RPM but usually performance suffers when dropping diameter on a sterndrive unless it's a very light boat.

 

[rau]

Re: newbie prop help

Re: newbie prop help

OK Thanks That explains
I'll just get the one you
recommended.Thanks again