I had my TopGun out last fall for last weekend of boating when I noticed my fuel pressure drop.

boat is a 38 Gun with Merlin 588’s Mooneyham 8-71’s topped with a pair of Holley 850’s. 850hp each.

I have Mallory 110 series electric pumps feeding mechanicals... the fuel pressure dropped because the electric pump failed. The boat ran fine on just the mechanical pump and held 5psi while cruising.

Now to my questions:

1. I’m assuming the point of the electric push pump is to just assist the long delivery of fuel to the motors mechanical pump. True?

2. Is it safe to run the boat with electric pumps off? I would have thought with the pumps off they would restrict or block flow of fuel...

3. Should I only use them when starting the engines to prime the mechanicals or should they stay on at all times?

thanks for input

You need to get the pressure up to around 7-8 psi, you lean it out on top and burn a piston, bad day. Id look at upgrading your mechanical pumps to support your HP & 7/8 psi stand alone but you can still run the electric ones for pushers.

1. yes
2. Id only do that in an emergency
3. no

Leave the electric fuel pumps on at all times?

with the electric pumps fuel pressure is up to 10psi sometimes.

running a regulator in front of the fuel feed to the carbs should hold steady at the setting no matter the input pressure
EDIT: if you're 5lbs at cruise without the electric pump I think they need replaced, what pumps are they ?..........some other guys will chime in

Mechanical pumps suck (literally) and is a great thing. Electric pumps don't suck very well, there is some but not that much. Once Elect is primed it will move fuel. This is why your Mech pump can pull fuel thru the Elect.

I would suggest, Mech first, then Elect after using a regulator to keep pressure at no more then 8 but 7 psi IMO would be better

Does someone have (or can draw) a basic schematic of the proven way to set up?

I could be wrong, I will definitely find out though, I’m pretty sure my electric pumps draw from tank, push to mechanicals, regulator, then feed lines with a return to tank. not 100% but will confirm.

I’ve put 40 hours, a poker run and boat ran 90 on gps with no issues at all before electric pump failed. It ran cruised 19 miles home on just the mechanicals with no known issue.

without knowing what pumps you are running it hard to make a suggestion , post up some pics

Speedy... I will get detailed pics soon when I can shoot down to the lake I’m next couple days.

here is the electric pumps...

Mine was originally set up that way . I bought 2 new electric fuel pumps with regulators and eliminated the manuel pump. Keep a spare electric on board for back up .
RG.

My thought exactly. Is there any reason not to do this? Any recommendation on pumps?