So took the boat to needles for Labor day. It ran the best its ever run. BBC, 049 heads, larger stainless valves, 10:1 comp, air gap mani, msd, 33 degrees timing, 750 holley vac sec, 292 Clay Smith solid lifter. So i see my opportunity to open it up. It goes to 5000 RPM and stays there and sounds beautiful!
My concern is that even though the rpm stayed consistently at 5000 while WOT, the boat SEEMED to pick up speed from initial WOT. It felt like it was still accelearating for about 15 sec? Is the pump slipping to where its taking time to fully pressurize? Does this make sense? Worn out pump?

A jet works on the principal of thrust over hydrodynamic and aerodynamic drag. What you experienced is fairly normal.

And yes, it's very possible the boat was gaining speed during the run.

Now you just need to figure out what out takes to get the hull out of the water sooner to shorten the ET. Maybe raise the nose  (Diverter  up) more and sooner to get some speed on the hit.

I would put a couple more degrees of timing into it,  trim up quicker and see where your at.

What secondary spring do you have in the carburetor?

GT

I honestly dont know what spring is in it. I had Performance Carb in Ontario (Ron Blanchard) tune it for my combo. Takes over 4000 rpm to get the boat on plane. No diverter yet. Over the winter i plan to get one.

Pump sounds tired to me,  should be able to plane the boat out at about 2500 rpm. Unless of course is a tank.

GT

Have you shimmed the bearing?

Hows the gap between the impeller and wear ring?

Was the cam broke-in while on the hose?

With a very similar set-up, I was spinning a stainless "B" Jacuzzi impeller at 53-5400.

Dan'l

I have done no work to the jet. I have no idea how the clearance is. I've never run the engine on the trailer while connected to the jet.

If im WOT at 5000 RPM, that means that if i rebuild the jet the RPMs will drop some if I'm loose.... RIGHT?

Right. Or most likely.

Tom @ JBP has WJ wear rings. Shimming it with a new wear ring will help a lot. A simple detail on the impy wouldn't hurt, either.

 BBC, 049 heads, larger stainless valves, 10:1 comp, air gap mani, msd, 33 degrees timing, 750 holley vac sec, 292 Clay Smith solid lifter.

BBC- 781 heads, stock size valves, Victor Jr. Rect. manifold, 1" spacer, 750 Holley VS, 292AH Comp squishy cam. Prestolite? dizzy, 32-34* timing. 9.78:1 C/R, headers.

Dan'l