PICTURES, can you help identify prop ?

[Billfo]

Readdressing my prop questions.(for understanding purposes). I understand that I EITHER need to go to a smaller diameter prop, OR reduce 1" in pitch to gain 150-200RPMs.

With THIS prop, I have another 300rmps to go for powerband at WOT. So I could drop 1" in diameter & or reduce pitch by 1" ?

I have NO idea what this prop is.. It is Aluminum & on a 2000 Mercury 135Optimax. This prop w/ insert is nothing like I have seen on my 150 nor 175 Evinrude aftermarket props.
It has a hub/spacer in the back, and a removeable insert in the front (held on by its spines & the prop nut). Please take a look at these pictures. I can not tell what the size & pitch is...left/right hand rotation ? Thanks for your help.
*** What I eventually want to end up with is a stainless prop & another 200-250 rpms. IF that will give me another 4-5 mph.

text on insert-

text on prop hub-

L & P on prop-

 

[Billfo]

Re: PICTURES, can you help identify prop ?

I found this information online.. Dont know if it is good or not..

Mercruiser Mercury schroef 21 Pitch te koop aangeboden ... - [ Translate this page ]Aangeboden: Gebruikte Mercruiser / Mercury aluminium schroef 21". Is te gebruiken voor binnenboardmotoren.
Gegevens : J14.25 X 21P nummer: 48-832832-C1-21 ...
------------------------
Confused myself completely..
If I want more top speed, dont I want to INCREASE the diameter of the prop ?

 

[Fun Times]

Re: PICTURES, can you help identify prop ?

I found this information online.. Dont know if it is good or not..

Mercruiser Mercury schroef 21 Pitch te koop aangeboden ... - [ Translate this page ]Aangeboden: Gebruikte Mercruiser / Mercury aluminium schroef 21". Is te gebruiken voor binnenboardmotoren.
Gegevens : J14.25 X 21P nummer: 48-832832-C1-21 ...
------------------------
Confused myself completely..
If I want more top speed, dont I want to INCREASE the diameter of the prop ?

The prop is a standerd mercruiser black max aluminum, right handed prop. The pitch is 21* the diameter is the 14.25, The 48-# is the part number for the prop from merc, The C in the part number tells you the prop is cupped. See link for what cupped means if needed.http://www.usedprop.com/boat-propeller-cup.php [this is a good site I just happen to find while looking stuff up for you]

This link is close to what prop you have from merc, But I could not find the cupped prop version.
http://www.mercruiserparts.com/SelectProp2.asp?propType=Black Max&pitch=21


This link is what merc has to offer in props, The best stainless steel prop that more then likely will work on your set up as an up grade to the aluminum prop you have now is the vengeance, It work varry well in most cases.
http://sites.mercurymarine.com/portal/page?_pageid=126,52105,126_52121&_dad=portal&_schema=PORTAL


To have more speed the best thing you could do is to make sure your engine stays within the top rpms your engine is able to do while trimed out as long as your engine set up will let you trim out a little bit at top speed. Yes bigger pitch will normaly be faster at top speed, But much slower on take off, But no matter what you need to be in the right top rpm range at top speed to save the engine from damage While trying to find the best all around performance you can. So bigger is not always better, From what you have said in the post You should stay within A 21 pitch prop, And if your boat is to slow on take off or the bow stays up to high to long on take off, Then you would want to go down to a 19 pitch prop, Also with all this keep in mind that a cupped prop will slow your rpms down Around 200 rpms in most cases, So going to a 21p none cupped stainless prop may already give you most of the 200 rpms I think you are looking for right now, Also a stainless steel prop is going to be faster with everything in most cases over an aluminum prop.


Understanding Propeller Cup
Many of today's propellers incorporate a cup at the trailing edge of the propeller blade. This curved lip on the propeller allows it to get a better bite on the water. This results in reduced ventilation, slipping, and allows for a better hole shot in many cases. A cupped propeller also works very well where the motor can be trimmed so that the propeller is near the surface of the water. The cup will typically result in higher top end speed on one of these applications.
Switching from an un-cupped to a cupped propeller will reduce your RPM. The actual amount of RPM decrease is dependent on where, how much, and the quality of the cupping. Typically, a cupped propeller of the same pitch and diameter will reduce your RPM by approximately 200. See this next link for more good info.
http://www.caravelleboats.com/propeller info.htm

 

[Billfo]

Re: PICTURES, can you help identify prop ?

Lots of good information. At least now I have an idea . Looking forward to spring to try out some things.. Thanks..

The prop is a standerd mercruiser black max aluminum, right handed prop. The pitch is 21* the diameter is the 14.25, The 48-# is the part number for the prop from merc, The C in the part number tells you the prop is cupped. See link for what cupped means if needed.http://www.usedprop.com/boat-propeller-cup.php [this is a good site I just happen to find while looking stuff up for you]

This link is close to what prop you have from merc, But I could not find the cupped prop version.
http://www.mercruiserparts.com/SelectProp2.asp?propType=Black Max&pitch=21


This link is what merc has to offer in props, The best stainless steel prop that more then likely will work on your set up as an up grade to the aluminum prop you have now is the vengeance, It work varry well in most cases.
http://sites.mercurymarine.com/portal/page?_pageid=126,52105,126_52121&_dad=portal&_schema=PORTAL


To have more speed the best thing you could do is to make sure your engine stays within the top rpms your engine is able to do while trimed out as long as your engine set up will let you trim out a little bit at top speed. Yes bigger pitch will normaly be faster at top speed, But much slower on take off, But no matter what you need to be in the right top rpm range at top speed to save the engine from damage While trying to find the best all around performance you can. So bigger is not always better, From what you have said in the post You should stay within A 21 pitch prop, And if your boat is to slow on take off or the bow stays up to high to long on take off, Then you would want to go down to a 19 pitch prop, Also with all this keep in mind that a cupped prop will slow your rpms down Around 200 rpms in most cases, So going to a 21p none cupped stainless prop may already give you most of the 200 rpms I think you are looking for right now, Also a stainless steel prop is going to be faster with everything in most cases over an aluminum prop.


Understanding Propeller Cup
Many of today's propellers incorporate a cup at the trailing edge of the propeller blade. This curved lip on the propeller allows it to get a better bite on the water. This results in reduced ventilation, slipping, and allows for a better hole shot in many cases. A cupped propeller also works very well where the motor can be trimmed so that the propeller is near the surface of the water. The cup will typically result in higher top end speed on one of these applications.
Switching from an un-cupped to a cupped propeller will reduce your RPM. The actual amount of RPM decrease is dependent on where, how much, and the quality of the cupping. Typically, a cupped propeller of the same pitch and diameter will reduce your RPM by approximately 200. See this next link for more good info.
http://www.caravelleboats.com/propeller info.htm