Name that prop

[df909]

I have a 4.3L with an Alpha 1 Gen II drive. After some talk on another post I'm going to change my prop to help out with hole shot. I don't know what size I have now and am open to suggestions of what I should take a look at. I've been told that a 4-blade would be a good move from my 3 blade I have now. I'm looking for more zero - go power to pull a skier and plane/plain (which is it?) faster. This is what I have now: aluminum 3-blade with the markings 49 78122 A40 21P. What's all that mean?

The boat's WOT RPMs should be around 4400-4600 but I can only get up to about 4200-4300, and that's with about 550lbs of people onboard. I also have a 3-blade stainless steel prop but it's pretty chewed up and bent. The PO apparently used it for exgavation.

What would you recommend? Thanks in advance.

 

[hwsiii]

Re: Name that prop

Df, you need to purchase a Solas Amita 4 blade aluminum prop in a 19" pitch and your RPM should rise about 200 RPM and your hole shot will improve dramatically.


H

 

[df909]

Re: Name that prop

Thanks for the reply. Will there be much difference between an aluminum & stainless steel? I'd much rather go with aluminum for the price.

 

[stylesabu]

Re: Name that prop

I would go with aluminum, because of price.I have heard that stainless is stiffer and that it will give you a little more power and speed than same size aluminum. but i have also had people say they couldn't tell the differance, go figure.hwsiii knows his stuff and he help me with the right prop choice for my boat.

 

[df909]

Re: Name that prop

This is what I have now: aluminum 3-blade with the markings 49 78122 A40 21P. What's all that mean?

Just so I know for the future, what do the numbers stamped on the prop tell you?

Aluminum it is and my wallet & wife are happy.

 

[Silvertip]

Re: Name that prop

The only part of the number on the prop that means anything to the consumer is the xxP which is the pitch. the remainder of the numbers are the manufacturers part number that identifies (to the manufacturer) the documents required to manufacture the prop. When you buy a bearing, a spark plug, an impeller, a hub cap etc you use a manufacturers part number to identify what you want. In a parts catalog that part number would identify what the diameter and pitch and the manufacturers "model name" for that prop is. Consider it like a UPC code on anything you buy at a store. It identifies what's in the box.

 

[180shabah]

Re: Name that prop

So you are thinking aluminum. Do you have any in mind? I would sugest the hustler/legacy for a good all around aluminum prop. It is still a 3 blade design, but it is vented, which helps hole shot.

Also, the WOT spec for your engine is 4400-4800RPM, so if you are currently making "full power" you are over propped and need to reduce pitch.

Service Manual 18 - for you engine

 

[slasmith1]

Re: Name that prop

I would take that stainless to your local prop shop and see if it can be repaired. You would be amazed at what they can fix.

 

[df909]

Re: Name that prop

I'm going to take the stainless prop to the repair shop and keep it as my spare. I notice that I can reach about 4400 rmp with it, but only 4300ish with the aluminum. I thought this was strange as the stainless is beat to heck and does not look good & the aluminum is in better shape.

It's got a 21 pitch on now, so I'm going to drop down to 19. I'm going to get a 4 blade per the advice and reading I've done here and I think I'll get it from iboats.com since they have this cool forum for us. I'd hate for their competitors to run them out and we'd lose the forum.

By the way, thanks for setting me straight on the service manual- I've been reading #7.