generalee31184

I have a 90' Checkmate Convincor 25ft, Currently has 454 with bravo, It has a 4 blade 26P bravo prop on it now. It currently does 55 On GPS and is only running around 3400 rpm. I really am new to these style boat and especially to understanding the prop set up and changing and what it will do. I will say with the current prop it pulls out the hole good and is obviously decent on fuel now only pulling 3400. I would like to get some more top end out of it that I know it has, so Where do I go from here?? Higher, lower P? Dont really understand it. thanks!

noyzee

sounds like something is way off!!!!!!

what 454 is in the boat? 300 hp, 330 hp?

and your sure about it spinning to 3,400 rpm not 4400?


if you are 100% reved out by 3400 rpm and your going 55 you have a rocketship on your hands esp if it h=gets on plane good.

sounds like something else is off, tach not right, something.
either way, im going to geuss from my boat and my testing that 300-330 hp would want a 22p 4 blade or maybe even a little less like a 21p 3 blade
i think 200 rpm or so per pitch change so even a 22 p will only be about 3600-3700

89Mach1

I'm guessing the tach is way off. I know a couple people with a 25 checkmate, one with the 330hp that runs a 23p mirage and the other with the 365hp mag that's running a 24p bravo 1. There's no way they are running 3400 rpm, I can tell you that. The guy I know with the 454 MAG runs a consistent 58-60, but has had it to about 64 at it's best. I'd say you're probably right in the ballpark of where it should be.

generalee31184

Well judging from what your saying, I guess the tack must be off. It appears to be an older tach, I dont know if the original tach. I will say just judging the sound of the motor it sounds like its opened right up and screaming along. Im just trying to think of way to check the tach before I consider replacing it. The motor has been gone through a few years ago, I just bought the boat this year, so who knows. Ok guys, I just went out and checked I was mistaken it currently has a 26P bravo 4blade prop on it!

Bigsbetter

I'm running the same boat and same prop you have right now....but a different engine. When my engine was stock, I was expiermenting with props in the 23 pitch range. ..23P Mirage, 23 pitch Bravo1, 22pitch Bravo 1 , 23 Pitch Hydromotive. That's where I would start if I were you. Ebay is a great place to expierement with props. Your current prop is a very nice prop, just not for your boat....right now. If it's in great shape it should bring 250-300 dollars off ebay and you can start expiermenting with others!

Bigsbetter

Oh yea, I haven't done the prop calculator on your speed verses rpm verses pitch, but I think I'm running about low-mid 50's around 3400-3500 rpm also, so I don't think your tach is off.

generalee31184

Hope im not sounding too stupid here, but am I wanting to look at 3 or 4 blade props? I believe I want 4 blad props correct? Is mirage style not a 3 blade? thanks alot for you help!

Bigsbetter

All the Mirages I've seen are 3 blade. Most Hydromotives are 4 blade, but there are also 3 blade Hydros. You can look for a Mirage or a Hydromotive or a Bravo1 are the 3 I would suggest trying. The 4 blade Hydyo's and Bravo's will spin close to the same of each other on your boat, the 3 blade Mirage in the same pitch will spin a couple hundred rpm higher than the 4 blade Hydro's/Mirages.

Bigsbetter

If you're asking weather you should be looking for a 3 or 4 blade prop...it's up to you. That's where the expierementation comes in. Finding the prop that works the best for your set up. Any of the 3 props I mentioned in a 22-23 pitch range would be a good choice to start out. Search around for one and find a good deal.

bbladesprops

A 26 B1 turning 3400 @ 55 mph would be -1.28% slip. Impossible.

Let us know if you would like to test some stock propellers.

B