want to know what will make me fly:)

rambler924

Cadet
Joined
Sep 19, 2005
Messages
8
I have a 25' custom made beachcraft hull, it has a very nice v that is alot like a scarrab's. Put twin evinrude 250's on her to give her a really nice kick. The props that are on her now are stainless steel 14 1/2 x 19 but everyone is telling me i might over rev with um and that i should get 21's. Looking for some more ideas. The props i just put on are 3 fin also. I dont know much about all numbers and stuff that have to do with all this so ya let me know. Finally got her in the water and gave her a run but i havnt had time to experiment with the props yet. Also i have not maxed her out but she should move. :D Thanks
 

ob15

Chief Petty Officer
Joined
Jan 4, 2004
Messages
514
Re: want to know what will make me fly:)

Need to know the rpm's along with the set up now & go from there.
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: want to know what will make me fly:)

These are 2 strokes, right? How are you going to "over-rev" them?<br /><br />What year are they? Is the counter gearcase on the port or starboard? Transom or bracket mounted? Stock gearcases or nose cones? Toe in or out?
 

rambler924

Cadet
Joined
Sep 19, 2005
Messages
8
Re: want to know what will make me fly:)

Ok, like my name stats im new to owning my own boat. The engines are 2004 Evinrude 250's ficht ram. dont know about the different mounting but they are just bolted to back of my boat, no platform or anything else. The engine on the left hand side rotates counter clockwise and the engine on the right side rotates clockwise. the engines are stock, onlt thing i have done to them is i had to change a coil on my left engine. Dont know what toe in or out is but im hoping this is enough info to get some response now. I *think* they are 2 strokes:O
 

rambler924

Cadet
Joined
Sep 19, 2005
Messages
8
Re: want to know what will make me fly:)

Ok ill try again. <br /><br />Engines<br />Twin 2004 evinrude 250's ficht ram. Left engine rotates counter clockwise right rotates clockwise.<br />They are salt water series.<br /><br />Props<br />Stainless steel 14 1/4 x 19 its the brand that has the tips but off the blades, sorry dont remember name.<br /><br />Boat<br />25' custom beachcraft fiberglass hull. Has a nive deep v alot like a scarrab.<br /><br />RPM<br />I think max rpm is 6300-6500 havnt really pushed it cause she moves and one day i lost traction on my left engine and she just starting reving high so then i dropped her to nuetral then took it slow.<br /><br />Dont know what a jackplate is so i am assuming i dont have one lol. Trim tabs are not currently hooked up. What i am looking for is kind of inbetween hole-shot and max speed. want to idealize my engines if i have to sacrifice the hole-shot so be it.
 

ivar

Petty Officer 1st Class
Joined
Jul 30, 2002
Messages
208
Re: want to know what will make me fly:)

its the brand that has the tips but off the blades, sorry dont remember name.
Like this ballistic prop? <br />
ballistic_prop_big.jpg
 

ob15

Chief Petty Officer
Joined
Jan 4, 2004
Messages
514
Re: want to know what will make me fly:)

OK, we're getting there. When the motor lost bite, did you have the motors trimmed up at all? Where is the anit-ventilation plate (AV plate from now on) in relation to the botton of the hull right in front of each motor? How far above or below is it? The AV plate is the big horizontal plate just above the prop.<br /><br />Do you know for sure that the rpms were 6300-6500 or is that a guess. What rpm were you running when the prop lost bite and were you in a turn? I'm assuming the boat has tachs for each motor. We will need some input as the the correct rpm we need for these motors (I'm not sure).<br /><br />I think if Dhadley or walleyehed check this post they will tell you that those are some real nice props.
 

walleyehed

Admiral
Joined
Jun 29, 2003
Messages
6,767
Re: want to know what will make me fly:)

As already stated, we really need a top RPM figure as a starting point....an honest wide open throttle RPM...<br />We'll discuss the Ballistics later.
 

rambler924

Cadet
Joined
Sep 19, 2005
Messages
8
Re: want to know what will make me fly:)

Yes that is the prop i had on when i lost bite. Lost bite at around 3500-4000 rpm, i was accelerating and i had tilted the engines up slightly to bring up the front of the boat. I was told i might have just hit dead water. I will have to check the rpms for you guys im pretty sure i ran up to 6400 but ill double check. I have different props on now so i will see. They are the same size but diff brand. Thanks for help, ill post more info after i figure it out. Ill also get the messurments you where asking for.
 
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