baron27

Hello i hope you can help me

i have a baha mach 1 29 foot with a 7.4 454 gen vi 330 hp
with a revelution p21 .

with this setup i can't get it to go over 43 with 4200 rpm
what could be the problem ?

the info i can find is that the original prop was a mirage p21 and that the top speed was 55.

dbkski

iTrader: (1)

Welcome!

However a 7.4L engine in a 29ft. boat will be a dog no matter what
you do. My 22ft. Mach 1 had a 7.4L B1 and did low 50's. That's with
a Mirage 21P. It was a bit slow to plane. Your boat comes in at
over 5000 lbs. empty. You need 200 more ponies!
But what you can do now is get a 19P Mirage Plus. No need for a
four blade prop with that low of HP. You did mean Revolution 4 21P
didn't you? That should work. Go have some fun. Then over the
Winter think about getting a bigger engine for 2013.

tinman565

I agree. Your setup is not meant for "hair on fire" speed. But, it should pull more rpm than that. You can try the 19P 3 blade, but thats prolly only gonna bring you up to about 4600 rpm. When was the last time the motor had a COMPLETE tune-up ? All filters, plugs, wires, cap, rotor, any adjustments needed...etc. I would make sure the motor is running the BEST that you can get it to. Also..your trimming it correctly right ? Cuddy isnt full of a 1000 lbs of junk from years of accumulation is it ? Is the hull bottom painted ? That alone can cause up to a 5 mph speed loss !!!.

And...I think dbkski meant to say 2012...which is next summer.

dbkski

iTrader: (1)

No I meant 2013. Get the right prop, have fun for a year, do some
engine research, then write a big ass check for a bigger engine!
Remember he has a 7.4L. 4600 RPM's is perfect.

bbladesprops

If you would like to test a 19 pitch 3 blade, let us know and we can send one to you.
I also believe this is the correct move.

http://www.bblades.com/pressreleases...essReleaseID=3

Brett