Spare prop?

[Jim13]

I think it would be a good idea to pick up a spare prop to have in the boat. Before I get one I would like your opinions on which one to get.

When I bought the boat it had an aluminum 14X17.

The boat is a 17ft. fish and ski with a 115 Johnson.

Today according to GPS 36 MPH at 5600 rpm with about 550 pounds of people.

I believe the operating range is 4,500-5,500.

Boat will be used for both fishing and skiing.

What size and pitch would you choose for a new prop?

 

[Crownie2]

Re: Spare prop?

What year is your Johnson?

At this point it seems reasonable to assume you could go with a SS wheel of about the same dimensions - check the iboats prop finder.

Bob

 

[walleyehed]

Re: Spare prop?

Regardless of year, I'd also get the RPM up to a minumum of 5800 with a normal load....I know, that's not what the book says, but the book wasn't published with 2006 model fuel in mind, unless that IS what year you have. The 14X17 OEM is the new style alum from OMC/BRP.

 

[Crownie2]

Re: Spare prop?

Regardless of year, I'd also get the RPM up to a minumum of 5800 with a normal load.

Isn't looper VS cross-flow an issue?

Bob

 

[Jim13]

Re: Spare prop?

Sorry, the engine and boat is a 97.

I just wanted to make sure I can pull a skier up and still have some top end.

The new prop will go on the boat and the old one will become the backup.

 

[walleyehed]

Re: Spare prop?

Crownie, crossflow=5800
looper=5900-6000
But, even 5800 on the looper is better than 5500.

 

[Jim13]

Re: Spare prop?

I'm lost. What the heck is a Crownie, crossflow or a looper?

All I know is that it is a 97 Johnson.

Your saying I should choose a prop to put me at 5800 WOT?

I could safely trim up a hair and pick up 200 rpm's.

 

[Crownie2]

Re: Spare prop?

Jim - Kenny was responding to my looper or crossflow question - two different intake systems used by OMC and the best maximum RPMs to use for each...

If you can trim up a little AND see a gain is speed, that is good.

Bob (Crownie2)

 

[walleyehed]

Re: Spare prop?

Sorry for the confusion there, Jim..

 

[Jim13]

Re: Spare prop?

Gotcha.

So, since I am sitting at 5,600rpm's at WOT, am I to assume that the previous owner actually did his research and selected the correct prop for this boat?

 

[walleyehed]

Re: Spare prop?

You're very close...
5800 would be a good target value, but you may be able to get that without changing props....Raising the engine 1 hole on the transom will usually net 75-150RPM depending on how the hull reacts and also the class of prop you are now running.

 

[Jim13]

Re: Spare prop?

Thank you very much sir!