Need Help Please

[mozbornj]

Boat is a Hurricane deck boat
21 foot 4.3 LX engine
Approx 4500lbs


I was running a Power Tech 3 blade SS 14.5x17
WOT was 4800 on the dot
speed was 38 GPS
This prop was fine for cruising but sucked out of the hole

I bought a new Solas Amita 4 to try
It is a 14.5x17
WOT is 5100 only ran it for about 5 seconds here
Top speed is 37 GPS
This prop launches out of the hole fully loaded with 9 people

Should I go with a 19 pitch 4 blade to bring the RPMs down to 4700-4800 or try to have some cup added to bring the WOT back a little bit?
Is there a good place to go to try to trade props with people, I bought it here at Iboats.

 

[hwsiii]

Re: Need Help Please

Moz, I need the year of the boat and motor and the gear ratio of the outdrive.

H

 

[steelespike]

Re: Need Help Please

When you change prop material all bets are off.It appears to me your having a lot of slip. You might try venting the SS prop.Perhaps add something like smart tabs.

 

[mozbornj]

Re: Need Help Please

1.84 ratio
boat is a 1996 model.

 

[countvlad]

Re: Need Help Please

1.84 ratio
boat is a 1996 model.

any idea what is the recomended WOT rpm range of the motor???

 

[mozbornj]

Re: Need Help Please

4400-4800 Wot

 

[hwsiii]

Re: Need Help Please

Moz, since you like the amita's pulling power I would just buy the 19" pitch version to get your RPM down. You will lose a little of your hole shot and your RPM will go down to between 4,500 and 4,600 RPM. You shouldn't lose any speed but you may gain a little.


Prop Change

H

 

[countvlad]

Re: Need Help Please

4400-4800 Wot

going with a 4 blade same pitch will bring your rpms down about 150 but you'll have better hole shot...

keep us updated

 

[mozbornj]

Re: Need Help Please

going with a 4 blade same pitch will bring your rpms down about 150 but you'll have better whole shot...

keep us updated

I went with a new aluminum 4 blade 17 pitch from a 17 3 blade stainless.
The 3 performed great except out of the hole it was slow.
I am happy with the 4 blade aluminum but I can't trim it up to high or it will over rev.
I don't have a prop shop or dealer around here that has an exchange program and don't want to buy 10 different props. Guess I'll get a 19p amita and see what it does.

 

[countvlad]

Re: Need Help Please

I went with a new aluminum 4 blade 17 pitch from a 17 3 blade stainless.
The 3 performed great except out of the hole it was slow.
I am happy with the 4 blade aluminum but I can't trim it up to high or it will over rev.
I don't have a prop shop or dealer around here that has an exchange program and don't want to buy 10 different props. Guess I'll get a 19p amita and see what it does.

it is normal for the 4 prop not be able to trim up too high.... there are cons and pros between the two props.... not beeing able to trim it up its one of the bad things about having a 4 prop...

just like everyone else around here, you learn it the hard way through trial and error...

 

[mozbornj]

Re: Need Help Please

I appreciate the help. If it is normal not to be able to trim up a 4 blade to high then I am spot on with my WOT. It is running exactly 4800 trimmed up 3/4 of the way. Just cuts the top speed a little bit no trimming up that last 1/4. Of course its a 4500 lb boat not built for speed anyway.
I can get 38 gps out of the new 4 blade also, the trim just had me thrown off alittle bit.

 

[countvlad]

Re: Need Help Please

I appreciate the help. If it is normal not to be able to trim up a 4 blade to high then I am spot on with my WOT. It is running exactly 4800 trimmed up 3/4 of the way. Just cuts the top speed a little bit no trimming up that last 1/4. Of course its a 4500 lb boat not built for speed anyway.
I can get 38 gps out of the new 4 blade also, the trim just had me thrown off alittle bit.

im not sure if everyone is going agree with me but i think going down one pitch might be ideal..... i think you are fine at 4800 as long as you dont go over or run it at that point all the time....

what was you speed at WOT with the 3 blade?

btw 3/4 of the way, do you mean the pointer is closer to the DN side or UP side? just wondering... on mine the sweet spot is in the middle of the gauge anything past that point my speed goes down...

 

[mozbornj]

Re: Need Help Please

3/4 of the limit switch. there abouts. The idiot that changed my bellows nicked a wire on the sending unit and it doesn't work half the time now. Just haven't had time to fix that yet.
But yes 3/4 when the gauge is working.