Help identifying prop...

[andy1canada]

Howdy,

Before I order my new prop I need to know exactly what it is I'm swinging now.

I'm pretty happy with the performance of this old Quicksilver/alum/4-blade and will keep it as a spare after I match it closely with an SS/4-blade.

I've narrowed it down (thanks WH) to the Stiletto BPII/4-blade... probably also in the 18 pitch.

What I need to know is - assuming the old prop is stock/unmodified - how much 'cup' it would have compared to what I will order in the new Stiletto?

More or less 'cup' will affect rpms...right?

I'm nearly at the top of my rpm range now 46-4700 (using the old prop on my 2007'/4.3/MPI/Merc/Alpha). So there may be one or two hundred rpm up for grabs still.

I'm thinking the switch to SS will likely produce that 1 or 2-hundred more rpm.

Logical?

I'm still breaking in the new engine but already (in a brief moment of euphoric demonic possession) I've crested the 45/mph mark. I'm figuring (hoping) that once I sand and paint her bottom (the boat's...) I'll see or break that magic 50-mph threshold.

If anyone can ID this prop, and tell me how much 'cup' it has I'd be much greatful. It's a 4-blade /14-1/2 inch/ aluminum and may be 20+/yrs old. Was on a 1980/305'/Chevy - Mercruiser.

Here's the hub numbers.

48 834852 (A45) 18p

Thanks in advance.

Cheers,
Terry

 

[Silvertip]

Re: Help identifying prop...

Stock Quicksilver prop - 18 pitch. What more ID do you need? If you are still breaking in the engine, wait until that is finished before buying a prop. As the engine loosens up it may pick up some rpm. Whatever new prop you end up with may have slightly more cup but trying to compare a 4-blade aluminum from one manufacturer with a stainless four blade from another manufacturer can throw you some curves. Performance with the old prop may not translate smoothly to the new stainless. True -- the stainless will likely be more efficient, but that may indeed rob you of a couple hundred rpm instead of gaining a couple hundred. On the other hand, if you are already in the WOT rpm window, a different prop may put you at the high side or even outside it. When it comes to fine tuning props it is best to try and find a dealer that will let you try before you buy.

 

[andy1canada]

Re: Help identifying prop...

Howdy,

Thanks Silvertip.

I understand where you're comin' from...

I know it's a stock prop (run of the mill) but I don't know how much 'cup'
it has compared to the Stiletto's.

Little cup?

Med cup?

Heavy cup?

Super-Duper cup?

Serious cup is like adding another degree of pitch, isn't it?

Cheers,
Terry