do these numbers sound right?

youstolemybeer

Hey all I have a 1995 265, (454 carb 22p stainless prop) and am now learning to drive it. Last year I spent most of the time in the slip fixing things. Now that everything is working as it should (except trim tabs) Im driving it more. I have found that I can stay on plane down to 23mph (gps) at 3100 rpm.  and at 4500 rpm Im hitting 37 mph.  Are these speeds acceptable for the 265?

Thanks
Steve

Handymans342

Have you played with the drive trim while at top speed? 

212rowboat

hard to know w/o knowing your gear ratio, but if you're running 1.8:1, @ 4500 rpm, you should tickle 47mph w/ 10% slip... 2.3:1 gear ratio and 10% slip, 37mph...

the gear ratio is printed on the drive, if it still exists... it may be stamped into the casing.. 10% slip is accpetable, whereas 5-7% is perfect.. you want some slip, just not that much and consistent. 

now if you're running 1.61:1 @ 7% slip? good times,  = 55mph...  if you can nail the top of the RPM band, @ 4800rpm, 58mph... 

youstolemybeer

I have no idea what the gear ratio is, its a 1994 bravo 3 if that helps.  I have played with the trim and found the sweet spot.
Thanks for any and all info

212rowboat

http://www.go-fast.com/Prop_Slip_Calculator.htm

You're most likely pushing 2:1 gear ratio with that big block... If so, you're slipping 20%, which can be fixed by either having that stainless prop worked, or, buying a new one.. 

What is your top engine speed? 4500 is at bottom of good.. I'd like to see you hit 4800, instead.  But, if the 22p is only letting you see 4500, its about right if not a little over propped... All things remaining consistent with prop geometry, a 21 will put you at 4700, and likely not drop your speed much at all.   

I'd like to hear what prop you're running, too.. blade geometry makes all the difference in the world.  if its not a progressive pitch, or if it is too progressive, that could be why you're slipping so much.  Three blade? Four?  and.. we'll know more about what to tell you with all that info.  .

youstolemybeer

its a 3 blade prop. give me some time and when I pull the boat out of the water Ill get back to ya.
Thanks
Steve