pantera232

I am running a new set up 462ci, air gap intake 750 holly, 7 psi fuel pressure, bob m cam, new distributer on way bc lack of total timing... 781 heads and domed forged pistons
Engine approx 450hp

The motor is running good its a little down on rpm's with a 21 pitch its running 4950rpm
Im hoping its bc not enough timing.
Regardless i put a labbed 23 pitch mirage and got about 63mph out of boat at around 4850 rpm

But the boat will run up to 4850 rpm then loose rpm to about 3800-4000 rpm then run up again if i back off and ease back on...

Im running 3/8 id fuel lines. it has 7psi at 900 rpm.. I do only have a 1" by 8" flame arrestor.
Some ppl are saying bigger fuel lines?
And other ideas?

stlliberator

iTrader: (1)

it will get to 4850, then drop rpm? Is the throttle still wide open? Or is it backing off?? I dont know why it would turn 4850 then drop rpm..I dont think the prop would be slipping that much..I would at least put a 3 inch arrestor on it..get some more air in that motor..

DMOORE

Whats the fuel pressure at 4900RPM's? If it is able to hold 7psi at WOT, it's not the lines. Double check the timing, then try running it without the flame arrestor just to be sure it's getting enough air.

Darrell.

pantera232

It will back down on its own, before i did motor old motor turned 4800 all day long