4.3 prop

[Michael33]

Hey guys,

So we had to get a new alpha one drive due to the theft of our other one. It’s a 1.62. It had a vengeance 19 p prop on it so I decided to try a 4 blade rev 4. Bought a 19 pitch per merc prop finder. Boat runs great but can’t get past 4200. That’s at 45 mph. Do I need to go down to a 18 or 17 pitch ? Boat is a Bryant 190 and it’s a carbed 4.3 2006 model. with the other Prop I could turn about 4600 with the same amount of people and fuel.

 

[kghost]

Typically for a 3 bladed prop, going down 1 pitch step, (21 p to 19 p) will give you a 250-300 rpm increase. I am not sure about the 4 bladed props.

Your engine most likely has a specification of 4600 to 4800 rpm.

So your desired target rpm should be in that range. So I would say if it were a 3 bladed prop I would say 15 pitch from 19 pitch. About a 600 rpm increase. This would put you right where you should be RPM wise.

So if someone can compare a 4 blade prop change in putch vs rpm that would be your answer for a 4 bladed prop.

 

[Michael33]

Typically for a 3 bladed prop, going down 1 pitch step, (21 p to 19 p) will give you a 250-300 rpm increase. I am not sure about the 4 bladed props.

Your engine most likely has a specification of 4600 to 4800 rpm.

So your desired target rpm should be in that range. So I would say if it were a 3 bladed prop I would say 15 pitch from 19 pitch. About a 600 rpm increase. This would put you right where you should be RPM wise.

So if someone can compare a 4 blade prop change in putch vs rpm that would be your answer for a 4 bladed prop.

Thanks for the reply, the specs on mine are 44-4800 so I’m just outside that window.

 

[Dieter]

Hey guys,

So we had to get a new alpha one drive due to the theft of our other one. It’s a 1.62. It had a vengeance 19 p prop on it so I decided to try a 4 blade rev 4. Bought a 19 pitch per merc prop finder. Boat runs great but can’t get past 4200. That’s at 45 mph. Do I need to go down to a 18 or 17 pitch ? Boat is a Bryant 190 and it’s a carbed 4.3 2006 model. with the other Prop I could turn about 4600 with the same amount of people and fuel.

on the rev 4 go down to a 16" or 17" the rev4 is a great prop but worlds of difference in terms of grab on the water vs your original vengance. Would think with a16" you would be close to 4800 rpm at WOT.

I have run a Rev 4 on my Sea Ray 200 sport (5.0/4bbl carb/1.81 drive) it is really nice if you run loaded down and do watersports. The one thing it is such a big prop that grabs the water, you need a lot of power to spin it, hence why you have to go down so much in pitch vs a basic 3 blade like the Vengeance. You can also experiment with the vent plugs to improve holeshot. For me the biggest benefit was stern lift and being able to fully trim out with out blowing out.

 

[Michael33]

on the rev 4 go down to a 16" or 17" the rev4 is a great prop but worlds of difference in terms of grab on the water vs your original vengance. Would think with a16" you would be close to 4800 rpm at WOT.

I have run a Rev 4 on my Sea Ray 200 sport (5.0/4bbl carb/1.81 drive) it is really nice if you run loaded down and do watersports. The one thing it is such a big prop that grabs the water, you need a lot of power to spin it, hence why you have to go down so much in pitch vs a basic 3 blade like the Vengeance. You can also experiment with the vent plugs to improve holeshot. For me the biggest benefit was stern lift and being able to fully trim out with out blowing out.

OK, got it, I really like the idea of a four blade Prop. I’ve run one on my bass boat and I really like the way it handles. I think I will order a 17 pitch, that should give me up into the middle of the RPM range hopefully around 4600, we do pull a tube and water ski, don’t typically have more than four or five people in the boat, 4200 with the 19 pitch was with my wife and two kids and about a half a tank of gas and the usual gear.

 

[Dieter]

OK, got it, I really like the idea of a four blade Prop. I’ve run one on my bass boat and I really like the way it handles. I think I will order a 17 pitch, that should give me up into the middle of the RPM range hopefully around 4600, we do pull a tube and water ski, don’t typically have more than four or five people in the boat, 4200 with the 19 pitch was with my wife and two kids and about a half a tank of gas and the usual gear.

you may find it more responsive through out the rpm range if it is propped to hit the upper end of the WOT RPM range. I can just tap the rev limiter if lightly loaded. Not that you have to run it that way just that it makes the throttle response better through out the rpm range and wont lug the motor as much when pulling a skier up loaded.

Of course best bet is to find someone who will let u swap pitches. I think Prop MD in MN and Ken at Prop Gods offer this exchange.

I too also have settled on 4 blades for my last 2 boats, you give up some top end but stern lift, lower planning speed and holeshot improvements are so much more useable for typical boating vs top speed.

 

[Michael33]

you may find it more responsive through out the rpm range if it is propped to hit the upper end of the WOT RPM range. I can just tap the rev limiter if lightly loaded. Not that you have to run it that way just that it makes the throttle response better through out the rpm range and wont lug the motor as much when pulling a skier up loaded.

Of course best bet is to find someone who will let u swap pitches. I think Prop MD in MN and Ken at Prop Gods offer this exchange.

I too also have settled on 4 blades for my last 2 boats, you give up some top end but stern lift, lower planning speed and holeshot improvements are so much more useable for typical boating vs top speed.

I agree 100% on the four blade. I went to a bravo xs on my bass boat and I can plain at a lower speed. It doesn’t blow out in a turn and the boat just handles better. I lost 2 miles an hour on the top end, but could still run 72 by myself. It also pops out of the hole almost immediately, that’s with two big guys 50 gallons of gas and a tackle store. I forgot about Ken Reeves. I’ve spoken to him in the past so I shot him an email with my dilemma and I’m waiting to hear back what he thinks I should try next. Don’t wanna keep spending $800 on props.

 

[Dieter]

I agree 100% on the four blade. I went to a bravo xs on my bass boat and I can plain at a lower speed. It doesn’t blow out in a turn and the boat just handles better. I lost 2 miles an hour on the top end, but could still run 72 by myself. It also pops out of the hole almost immediately, that’s with two big guys 50 gallons of gas and a tackle store. I forgot about Ken Reeves. I’ve spoken to him in the past so I shot him an email with my dilemma and I’m waiting to hear back what he thinks I should try next. Don’t wanna keep spending $800 on props.

i bought all mine on ebay used. Took some time but I was able to try 5 or so props that way relatively inexpensively. Sold off the ones I really didnt like

The Vensura/Offshore prop also worked pretty well for me, I got better holeshot than the Rev4, but had a lot of slip on top end and couldn't trim out as much