Is my new prop OK?

[packman35]

When I bought my boat, the PO had a 17P prop on it. It was chewed up quite a bit so I wanted to replace it. Hole shot is not that important to me so I opted for a 19P Hustler prop. I tried it out last night and noticed a couple things. First, the hole shot is definitely less. No big deal. I also noticed where the 17P prop at WOT was at 5500 and pushing me at about 37mph, the 19P is at 4800 at WOT and pushing me at about 39mph. This is as expected.

My question is this. The engine is rated for WOT from 4500-5500 and at rated power at 5000 - per the shop manual. I don't think I am lugging the engine since I am still in the recommended range even though I can no longer achieve 5500 rpm. Is this correct? Or should I go back to a 17P or perhaps compromise at an 18P?

FWIW, 19P is what the boat shipped with from the factory.

Thanks in advance. I just want to make sure I'm not tearing anything up!!

 

[Dhadley]

Re: Is my new prop OK?

You didn't mention what motor you are using it on so we'll assume it's the 115 in your signature. We also have to assume about the year of the motor but since you mentioned the old rpm rating we'll further assume it's an older crossflow.

If that's the situation, yes you're lugging it. With todays fuel even 5500 is borderline lugging it.

 

[packman35]

Re: Is my new prop OK?

Yes, it is a 1993 115TLET.

Am I lugging it even though the recommended range is 4500-5500? I guess I don't understand that part.

 

[Dhadley]

Re: Is my new prop OK?

Combustion temp is what it's all about. Not necessairly related to water temp btw. When the motor is working hard to achieve any rpm, 3000 or 6000, the combustion temps go up beyond design parameters. That leads to coking and stuck rings which can / will lead to broken rings.

 

[steelespike]

Re: Is my new prop OK?

Your chewed up prop may have been adding artificial rpm that would have disappeared with an identical replacement then you changed design and pitch.
I'm no Hustler expert but I would think a 17 would run closer to its designed rpm range.And will surely have better hole shot and may get the boat up better.Will it get you to 5,500;probably not but should get you to about 5,200. I've read here some amazing results taking a little cup out of a prop.
Don't know if recommended with a Hustler.
Forgot to mention the Hustler may allow you to raise the motor a hole or 2.
for more speed and rpm.Not enough to use the 19 but may improve the
Hustler 17s 5200.

 

[packman35]

Re: Is my new prop OK?

Thanks guys for the advice. I think I will see if iboats will exchange the 19p for a 17p and see what that does for me.

I am still confused as to why it's bad thing that I am running within the mfg's recommended range - albeit not at the top of it - but I will trust you all as you certainly know more about this than I do!!

I guess it all comes down to prop design too. Four Winns shipped this boat with a 19p on it which is why I went to one. I guess the Hustler just performs differently than the OMC one it came with.

Thanks again for the input.