Looking for a different prop

[Ron-O]

Right now my prop is a Stainless Quicksilver 48-16316A4-19P. From research this is a 19 pitch but can't find anything else on it.. With the 4.3 in the boat, once trimmed out I have to watch the tach so I don't go over 4800rpms, it will try to climb above that. I was thinking about going to a aluminum or composite prop since I'm in the Ohio River and it's real easy not to see a submersed log at times. Any suggestions?? I can get 58 mph or so with what I have now and one 2 people in the boat. I like the speed but I cruise more than doing fast runs.

Mercruiser 4.3L
Alpha 1
Gear: 1.84:1

 

[Ron-O]

Re: Looking for a different prop

From talking with the techs at Iboats.. Looks like my best bet is a 4 blade 14x19P to drop the rpms by 100 or 14x20p to drop the rpms by 300. Sounds about right?

 

[trendsetter240]

Re: Looking for a different prop

From talking with the techs at Iboats.. Looks like my best bet is a 4 blade 14x19P to drop the rpms by 100 or 14x20p to drop the rpms by 300. Sounds about right?

Depends which prop you are buying as the replacement. Different prop manufacturers and blade designs will have a different effect on RPM and performance.

For example I have 2 17p props that give WOT RPM 500 apart. So you can't really say that any 19p prop will give you that exact result.

You are on the right track, I'm thinking a 4 blade 19 or 20 pitch will be right for you but if you provide more details on your current setup someone here can help you to get it dialed right in.

Solas makes good aluminium 4 blade props. They sell them right here from iboats.com.

 

[hwsiii]

Re: Looking for a different prop

Ron, I don't know what to tell you, but can't get 58 MPH out of a 1.84:1 drive turning even 5200 RPM and that prop, you need to get us a GPS speed and actual RPM in order for us to tell you what prop you need.



H

 

[Ron-O]

Re: Looking for a different prop

Depends which prop you are buying as the replacement. Different prop manufacturers and blade designs will have a different effect on RPM and performance.

For example I have 2 17p props that give WOT RPM 500 apart. So you can't really say that any 19p prop will give you that exact result.

You are on the right track, I'm thinking a 4 blade 19 or 20 pitch will be right for you but if you provide more details on your current setup someone here can help you to get it dialed right in.

Solas makes good aluminium 4 blade props. They sell them right here from iboats.com.

The prop I'm thinking about is the Michigan Vortex 4 blade 14x20P. The boat will over rev now with the stainless 14x19P prop on it now, but I don't worry about it since I've been the only driver and keep a close eye on the tach. Usually there are only 3 of us on the boat just cruising, no skiing or tubing. Does just going from stainless to aluminum change the rpms, keeping pitch the same??

 

[Ron-O]

Re: Looking for a different prop

Ron, I don't know what to tell you, but can't get 58 MPH out of a 1.84:1 drive turning even 5200 RPM and that prop, you need to get us a GPS speed and actual RPM in order for us to tell you what prop you need.



H

Yea, that speed is only based on what the fishfinder said..not any gps reading. Can't get a GPS reading yet since the boat hasn't been in the water this year. With my 4.3L, WOT is only supposed to be 4400-4800.

 

[180shabah]

Re: Looking for a different prop

58mph with that drive and prop would require more than 6500RPM, and that 4.3 will NOT do it - valve float will show up much sooner.

We really need some accurate numbers to give any meaningful advice.

 

[Ron-O]

Re: Looking for a different prop

58mph with that drive and prop would require more than 6500RPM, and that 4.3 will NOT do it - valve float will show up much sooner.

We really need some accurate numbers to give any meaningful advice.

Yep, I went through some of the prop pickers online. Looks like my speed on the fishfinder is wayyyyyyy off. Thought it would be more accurate than the regular speedo, thought wrong. I'm trying to get the boat in the water this weekend, maybe I can do some tests then.

 

[hwsiii]

Re: Looking for a different prop

Just let us know when you have some new numbers.



H

 

[Ron-O]

Re: Looking for a different prop

UPDATE:

I was able to pick up a Michigan 4 blade 14X20P prop to try. My first run was yesterday taking the boat to the marina. With me and my daughter in the boat rpms were right at 4900 trimmed. I figure with one or two extra people that we usually have in the boat it should be right between the 4600-4800 WOT. I did notice the 4 blade aluminum has more torque steer getting up on plane but she does run real nice. Need to check the speed with the GPS just to see. ( I did have to grind my anode a little to make sure it didn't hit)