https://parkeraz.chambermaster.com/events/details/sandbar-resort-s-first-last-show-and-shine-hotboat-regatta-11309

Possibly this?

Dan'l

Welcome back again, Glasscutter.

Dan'l

November 24 & 25 - The Blue Water Resort & Casino Absolute Speed & Marine 77th Annual Thanksgiving Regatta Presented by Nick Rose Insurance, Frederick & Son's Heating &  Air, RaceTec Pistons, Parker Oil

First off, fuel. Get rid of it. Inspect tanks for varnish, etc.
Fuel filter(s). Fuel pump might be done too. Pay attention to the fuel lines. Probably done too
Grease front pump bearing.
Grease driveshaft
Check lube in bowl. Add oil or grease as needed.
Holley carb will possibly leak after sitting so long.
I'd either pull the distributor and prime the oil system, or disconnect the ignition system and crank until you have oil pressure.
Start with a known good/new battery.
I'd probably pull all the plugs to inspect.
Check all the water hoses.
I'm probably missing something.
That's a start.

Dan'l

I KNOW! I shouldn't worry about fuel efficiency if I'm ripping a bbc jetboat, but i burned right  through 40 gallons in a day and was kind of taking it easy. Im firing on all cylinders. I was just wondering if everyone else is burning right through fuel or if i have a problem somewhere. Would a efi throttle body help at all? I've got a 650 edelbrock with an electric fuel pump on top of a bbc 405 right now. My pump set up is a little odd but I don't ever feel like its sucking air. Has anyone figured out how to get a little more miles to the gallon? Any tips or tricks anyone wants to share would be greatly appreciated!!!

Sent from my SM-S916U using SoCal Jet Boats mobile app

What impeller do you have? And how long has it been since a refresh on the pump?
Larger impellers tend to get better fuel efficiency.
As does a tight pump.
Even with a SBC, I run an A cut impeller.

Food for thought.

Dan'l

I got mine from PTO sales in Phoenix.

Dan'l

Where to start?
My old azz eliminator day cruiser is supposedly a 3800 lb hull, per Eliminator. Then add a 454 and pump (650 lbs?) and (2) 25 gallon tanks, and all the BS for a day on the river, I'm guessing at 4800 lbs?

Bigger boats need bigger impellers. Mine runs a AA from American Turbine. It's slightly larger than a 2A from Berkeley.
With ~500 HP,  turns the AA to 4950-5000 rpm, at a blistering 57 mph, going up river, with 3 others and myself. Would probably hit 60 by myself and minimal fuel.

Tows grandkids on inflatables easily, and a 275+ lb single skier without hesitation.

Floats in ankle deep water (avatar pic)

Big enough for Mohave, but easy enough for the river at Bullhead.

Dan'l

Could the splines be twisted? That would cause the interference fit and the vibration issues.

A new or good used shaft should be easy to source.

Dan'l

That would do it (cavitation)
Does the area around the hole seem thin, vs the rest of the pump? Check closely.

Dan'l

There's several marine dizzys that are no longer made. Prestolite possibly. Check thru sierra marine.

Dan'l

Fuel vapor is heavier than air, so it settles down in the bilge.

Especially if it is already rigged with one, I'd get it working properly.

It only takes one spark with the ideal conditions to ruin your weekend.

Dan'l

I'd check the radial clearance.
It should be .012 inch per side or so, about .025 total.
I checked at 3 and 9 o'clock.
I've measured .035 inch per side on a sloppy pump.
A properly fitted wear ring fixed the problem.

Dan'l