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Cruzzze
05-14-2006, 03:53 PM
I have a 25' Eliminator Eagle with a 454 and mercruiser, and a Vengeance 21P prop, and at 3000' the boat starts to really spin the prop and only runs about 54 mph. The motor will spin up anoth 800 rpm and of course the boat starts to slow. What prop would you recommend? Thanks for the help.? The motor is stock by the way. Thanks

bigblockbill
05-14-2006, 04:07 PM
Sounds like you are trimming the drive up too far. There comes a point where as you trim up you can actually start slipping the prop and have to trim it back down a hair. The faster your going the further you can trim the drive up before the prop starts to slip. That is normal and can happen with any prop. What you need to do is select the lowest pitch prop that you can still achieve near red line rpms with 1 person in the boat and the prop not trimed up so far it is slipping like that.

bordsmnj
05-14-2006, 04:58 PM
tried a bravo 22?

bordsmnj
05-14-2006, 05:03 PM
tried a bravo 22?
mercury marine used to have a "prop selector" thing on their website. you type in your boats wieight ,horsepower,gear ratio,etc and it spits out a few props that might work. i have a 20" three blade for but it sounds like you need the hook up of a four blade. the rev4 from merc has some pretty good bite in the mid range.

JustDawn
05-14-2006, 06:17 PM
What altitude are you running at?
I used to have a 25 Eagle w/502...At Havasu I would run a 26p bravo 1.
Here in New Mexico I ran a 24P (approx 5000 ft.).That 21 is way to small,sounds like you are blowing it out....
Your best bet overall is a 4 Blade Bravo...the boat handles better,and you can carry more weight with a 4 blade.
That particular hull is designed to run loose,so you can actually run with a lot of positive trim... :boxed: (PlayDeep)

BadKachina
05-14-2006, 06:52 PM
If I remember right I had a friend with that exact same set-up and he ran a 22 pitch Bravo 1 in the low 60's. The four blade Bravo has a little bit bigger diameter than the Vengence and an extra blade. It should get your slip down some, and give you a better hole shot.
If you're losing speed you are probably trimming too high. Your boat, if stock, should have a trim limiter and a trailer button. Your drive should not trim past 21 3/4" with the trim button (measured bolt to bolt on your trim cylinder). If you don't have a trailer button and your trim button will lift your drive all the way up then measure out 21 3/4" and make a note of it on your trim gauge. Any more trim than that while running is bad for your u-joints and gimbal bearing.

BALLSDEEP
05-14-2006, 07:10 PM
Wrong prop! I have the same boat with an HP 500 and I run a 26 pitch 4 blade. Talk to a prop guy or call Eliminator direct to see what they recommend.

bordsmnj
05-15-2006, 01:02 AM
with that small of a prop i was thinking that he's gotta have a higher gear ratio than 1.5 typical.

Cruzzze
05-15-2006, 06:23 AM
I just bought the boat a week ago, and the original 502 was replaced with a 454 mercruiser stock. I'm running here at 3000' and Lake Powell is about 3700' so relatively mid altitude. I was going to ask ( as someone already said ) if there is a prop selector somewhere on the web to look at. Thanks for the help.

bilgewiper
05-15-2006, 06:58 AM
try this, might help
http://www.rbbi.com/folders/prop/propcalc.htm

Cruzzze
05-15-2006, 07:15 AM
It's a 1.5 ratio drive........using that prop calculator is great, says at 4500 rpms at 53 mph with the 21P 3 blade, it's a .111 prop slip. Is that good or bad?

bilgewiper
05-15-2006, 07:29 AM
I would "think" with a boat that heavy there would be a larger "prop slip"
factor. Are you getting your boat speed from GPS?

BOBALOO
05-15-2006, 07:44 AM
I have the same boat as you. The 25 Eagle from what I have been told runs the best with a 4 blade Bravo prop. The steps on the hull create too much turbulance or something and this causes the prop to blow out.
I have an open bow and 454 mag in mine and ran a 22 pitch Bravo 4 blade to about 5100 rpm at 65mph 2 weekends ago in Havasu. The abused 24 pitch Bravo prop I have turns about 4800 rpm at about 64 mph. This was with a load of 5 people 4 coolers 2 anchors, tool box ,bbq, 3 batteries, large stereo,beach chairs, you get the picture, lots of weight.
Try a 22 pitch if you carry alot of weight or b/c of the high altitude. Lots of people sell them used and you should be able to find one for about 300$.

Cruzzze
05-15-2006, 07:45 AM
Yes that was GPS

BOBALOO
05-15-2006, 07:56 AM
Heres mine, it's older but I did'nt have to take out a second to buy it. I really like the boat and have had it for 3 years.
http://www2.***boat.com/image_center/data/520/1914DSCN3624.JPG

Cruzzze
05-15-2006, 08:20 AM
Bobaloo, first of all, nice boat. Second, your deadon, I just talked to Eliminator, and they said that with the 454, they put them out with a 4 blade bravo1 22 or 24p. I think I'll try the 22 bravo1 4 blade and hope it works....what year is your boat?

BOBALOO
05-15-2006, 08:25 AM
Bobaloo, first of all, nice boat. Second, your deadon, I just talked to Eliminator, and they said that with the 454, they put them out with a 4 blade bravo1 22 or 24p. I think I'll try the 22 bravo1 4 blade and hope it works....what year is your boat?
365 horse 454 mag carbureted.