Am I running the correct prop?

[DYLBOSS]

I ask this, because I'm about to purchase a second prop as a spare, but was wondering if the one that I'm running now is even the right one.

To answer the standard questions.....

1. No performance issues that I can tell. (only second season with boat)
2. Not sure of the prop manufacturer or model, aluminum
3. Not sure, but it says 19 16 19 on the prop
4. I think the WOT is 5500 at about 50mph
5. Engine is 1996 Merc 5.7L w/ Alpha 1 OD 260HP
6. Boat is 1996 Rinker 212 Captiva Cuddy, 21ft , 3000lbs avg.

Thanks for any help.

 

[hwsiii]

Re: Am I running the correct prop?

Boss, we need some more numbers off the prop, I can't tell if it is a 16" pitch or a 19" pitch, probably a 19" but I need to know for sure.
I also show your maximum recommended RPM should be between 4,400 and 4,800 RPM with a 1.47:1 Gear ratio, please verify this.



H

 

[DYLBOSS]

Re: Am I running the correct prop?

Sorry, that is correct. I meant to say 4500 not 5500. As far as the numbers, I can't seem to find anything on the prop other than 19 16 19. Is there somewhere else I should be looking? Do I need to remove it and look in the shaft section?

 

[DYLBOSS]

Re: Am I running the correct prop?

Boss, we need some more numbers off the prop, I can't tell if it is a 16" pitch or a 19" pitch, probably a 19" but I need to know for sure.
I also show your maximum recommended RPM should be between 4,400 and 4,800 RPM with a 1.47:1 Gear ratio, please verify this.



H

Ok, so I looked a little closer, and it is showing that I have a 14.5 x 19P prop on there. I called Rinker and they said that I have either the standard 5.7 or the 5.7LX. The standard came with the 14.5 x 19 and the LX came with 14.25 x 21.

I am now second guessing what I have. The previous owner said that it has 250HP, but now that I know this I'm not sure. I don't see anywhere on the engine that says LX. The serial number is 0F772626. Tried looking that up but it gives me both models. I can either assume that I'm running the recommended prop and have the standard 220HP version, or I have the LX with 250HP and am running the incorrect prop.

Confused

 

[hwsiii]

Re: Am I running the correct prop?

Boss, I need to have exact numbers for RPM and speed to find you a better prop. The next time you have a chance will you take it out and run it and get me an exact WOT GPS speed and RPM.



J

 

[DYLBOSS]

Re: Am I running the correct prop?

Boss, I need to have exact numbers for RPM and speed to find you a better prop. The next time you have a chance will you take it out and run it and get me an exact WOT GPS speed and RPM.



J

I did check this last season. I was running between 4500 and 4600RPMs at 49/50MPH. I also just got off the phone with MerCruiser. They told me that according to my serial number, I have the standard 5.7L, which is 210HP with 1.62 gear ratio. Looks like the guy that sold it to me either lied or was not properly informed.

 

[hwsiii]

Re: Am I running the correct prop?

Boss, I am showing you have a 3% prop slip, and your boat is doing fine.



H

 

[DYLBOSS]

Re: Am I running the correct prop?

Boss, I am showing you have a 3% prop slip, and your boat is doing fine.



H

Great, thanks hwsiii. I guess I'll just stick with the 14.5 x19. I remember reading this somewhere in one of your posts, but at what % would it not be a good prop slip?

 

[hwsiii]

Re: Am I running the correct prop?

Anytime I find the prop slip over 15% I recommend that people need to change to a new prop with a different blade geometry and design. Actually 3% is too low, but I assume that your numbers are not exactly right, so thus I think you are fine.



H

 

[DYLBOSS]

Re: Am I running the correct prop?

Anytime I find the prop slip over 15% I recommend that people need to change to a new prop with a different blade geometry and design. Actually 3% is too low, but I assume that your numbers are not exactly right, so thus I think you are fine.



H

Thanks a lot for the help. I actually just found your thread on prop performance with the formulas and such. Very helpful info.

 

[hwsiii]

Re: Am I running the correct prop?

Boss, I will have to say it warms my heart when people tell me that they have found information in my posts to be helpful and increases their knowledge base about props.



H

 

[DYLBOSS]

Re: Am I running the correct prop?

Boss, I will have to say it warms my heart when people tell me that they have found information in my posts to be helpful and increases their knowledge base about props.



H

I do really appreciate the time and effort that you and others have put into this forum. I have absorbed a wealth of information in the off-season! I'm a DIYer at heart and love to learn, so this has certainly been the place for me to take on my new hobby. Totally obsessed as my wife would say.

Funny enough, I recently talked to a guy that has been boating for years. I'm a newbie as of last season. I was actually teaching him a lot of stuff that I learned on this forum! Amazing.

So, now that I have gotten the correct prop info down, on to finding out which manufacturers are the best bang for the buck. Not into top notch, just functional and reliable.

Thanks again!

 

[DYLBOSS]

Re: Am I running the correct prop?

Boss, I will have to say it warms my heart when people tell me that they have found information in my posts to be helpful and increases their knowledge base about props.



H

Hwsiii, question for you. I started a new thread on RPMs and was hoping you might chime in. Could be prop related, but not sure. I'm a little confused. Thanks.

http://forums.iboats.com/showthread.php?p=2635100&posted=1#post2635100