Thread:

BBF wont run right

To recap: 17’ Sutphen (see avatar) "everything" rebuilt

re-built 460 20 over w/mild headwork (exh 2.190 int 1.710)
800DP Holley rebuilt
All Mallory ignition (6m-2c, blaster 3 coil) and wires
re-built and blueprinted Berkeley pump by ARS w/stuffer & place diverter and new grate stuff
Edlebrock Performer 460 manifold (specs say it needs 9.5-1 comp)
Crower 460 cam (specs say it needs 10.25-1 comp)

Previous owner was going to put a blower on it and therefore had 8.1 compression on rebuild…would this cause the problems since cam and intake seem to be a miss match…

Here is the problem…boat will come out of the hole fine but when it hits around 3500 rpm it hesitates as if you are holding on to it…kinda like a skiier on the back end pulling hard across the wake…it tops out around 45mph or so …and it just wont “open up completely”…don’t know how to describe it better than that…secondaries are opening up and nothing messed up in pump or grate…timing is around 30 degrees…

Any thoughts would be most appreciated

That sounds like a terrible setup. An engine with no compression, a cam that's way too big for the setup and probably an A or so impeller? Also is 30 timing the total advance? Probably a bunch more advance would help with the low compression and all the mismatched parts. Get some boost or some new pistons and maybe a new cam....depending what the actual spec of it are and what direction you end up going to fix these issues. I'm sure it'll be asked, but do you have the cam specs?

AP

Talked to RiverRacer a couple minutes ago. I asked him about your engine. He said to tell you to try 38-40 degrees advance. The quicker it's all in the better, but it should all be in by 3500 even with a stock Distributor. You will have to run lots of initial if it's a stock type, but it will help the engine thru it's problem area.

Agree! Run it on the trailer, see if it opens up. Then with it in the water under a load, I would lean towards ignition also.

manual or electric fuel pump?

It could be both Fuel & Ignition. One of my boats is a 20ft, heavy, Spectra cruiser with a stock 460 and a Berk 12-JC stock in need of work. After I took out the Prestilite disty and threw it as far as I could, I put in a MSD & spark plug wires and plugs. Timing is set at 34degrees. Would rev up real good on the trailer, put a load on it in the water and would start cutting out. Put another fuel pump on it and pressure would now hold at 6 to 7psi on a 750 DP. Motor now spins upto 4900 and GPS at 56mph and this is with a pump that needs to be gone thru.

With your tight pump, you should be spinning up to maybe 4800 and be running in the 60's in a 17 ft boat.

dang it...the ignition is not mallory but a complete MSD with marine cdi igniton 6M2L...marine distributor...and coil and wires...the advanced timing is controlled in distributor by weight springs and advance cam stop bushings...sorry for the screw up...
some cam specs are:ADVERTISED CAMSHAFT SPECIFICATIONS:
INTAKE: Duration: 311º Lift: .588 Clearance Hot: .000 EXHAUST: Duration: 316º Lift: .604 Clearance Hot: .000
ULTRA PERFORMANCE COMPU-PRO / PERFORMANCE LEVEL 4Dual purpose hot street/strip camshaft. Delivers strong mid-range
and top end torque and horsepower.
RPM Power Range: 2000 to 6000 / Redline: 7000 plus.

Of course you could use more compression. But I'm leaning more towards what bp298 said, you may not be getting fuel to the carb. Check your fuel pressure at the carb under load, up the timing and go from there.

i agree with ap.
that cam sounds way big for 8:1.

done a compression test? that would say a lot.