Eliminator 21 daytona 225 pro max prop choice.

[EliminatorJEFF]

Hey guys I just bought this boat, its a 93 daytona with a 96 225 pro max just rebuilt with all the best parts. I want more top end speed with the boat, It runs high 60's at about 4500 rpm. I'm running a mazco 28p 4 blade. The person that rebuilt the motor said I should be getting like 6500 rpm. The boat takes awhile to plain also with this prop. once its up it has great bottom to mid range power but I feel this motor has way more potential on the top end range. Any advice for prop set up to get the most top end would be great. I am also new to the outboard world. Thanks guys much appreciated.

Jeff

[specboatops]

I think I'd try a Trophy, maybe a 25" or a 26" .....

[GETBOATS]

start with the basics and find a merc guy that can check compression, sync and linkage adjustments timing etc. need to make sure your engine has what it needs to produce its power. don't over look the tachometer, verify its accuracy. but I wouldn't run it with rpm that low at wot, you can cause lots more trouble inside, try a smaller prop (pitch) to see if will run up. from there, engine height. you didn't mention trim position, if its all the way trimmed in the symptom would be similar. lots of Daytonas on here to compare prop info when you get to that point. but again when things don't seem right, eliminate to the easy stuff first. good luck

[capteliminator]

That's a big heavy boat that needs bow lift. I suggest a 26 chopper or mazco RE3.

[stokernick]

26 Lightning ET

[tux974]

Not familiar with your hull but familiar with the 225PM. Like suggested you need to drop down on pitch. 24,25 if you going 4 blade, 26 3 blade if all else is correct and you are only pulling 4500 on that 28.
6500+ is correct for that motor.

[David]

I think the tach is wrong. My prop calculator shows negative slip at 68 mph, 4500 rpm, 1.87 gears, 28 pitch. Unlikely.

http://www.rbbi.com/folders/prop/propcalc.htm

I would have thought that a Mazco RE4 would have lots of lift.

[EliminatorJEFF]

Thanks guys for your responses, Is it true the less blades and lower the pitch makes more top end? Sorry I'm new to this. I'm coming from a jet boat. How are the cleaver props?

[F14]

You may need to have that motor checked out. I think it should spin that 28 close to 6500 rpms. Do you have a jack plate? My 21 was fastest with the center of the prop shaft 1.5-1.75" above the bottom of the pad / boat.
The 21 Daytona is a efficient fast hull. Mine ran 105 with a 300XS. You should see 85-90 I would think.
Find someone who has some props that you can try. Good luck and have fun.

[panther150]

as mentioned above , with your motor trimmed so the propshaft centreline is parrallel with the bottom point of the rear of the hull , if you have a manual jack measure the distance between the propshaft centreline and the bottom of the hull, is it above or below? if you have a hydrallic plate put it at full lift and measure. propshaft height makes a big difference in rpm and speed if you are way too deep now. You should be pulling that 28p RE4 higher than 4500 I would think .do this first and post your findings. If you are way low, set it to the above posted heights and try. Make sure you have a working water pressure guage before trying this.

Steve

[EliminatorJEFF]

I have a hydraulic jack plate. Is it safe raise the jack plate without a low water pickup? What is the minimum water pressure I should be getting when it is raised. Thanks for your input

[F14]

I assumed you had a low water pick up. If you dont and you want to go fast, get a lower unit with a low water pick up.

[GETBOATS]

I have a hydraulic jack plate. Is it safe raise the jack plate without a low water pickup? What is the minimum water pressure I should be getting when it is raised. Thanks for your input

Not a Merc guy, but i'd think nothing less than 12-15 lb range.

do you have a prop, any prop in the 22-24 range, start with the anti-ventelation plate 3 inches above the bottom, find zero degrees trim and see how it runs there. assuming all else checks out with the engine. and the tach is accuate.

[panther150]

post a pic of your lower from the side, looks like a cle or coned unit already. 15 lbs of water pressure and up is considered safe.

Steve

[pyro]

Something's wrong here... The numbers don't add up. The tach is probably wrong, for starters. But there's more. These boats should run 80's with a 225 Promax, not 60's. Several have supposedly ran over 90 running light. There's got to be some major setup issues.