Tom

Ken of HTM built my motor jsut before the accident and I am just getting around to preparing my boat for driving. Can someone please help me with answers to some questions?

HTM 560 inch - 650 HP engine
holly carb - can't find any numbers
Holly distributor
Holly computer?
Holly black pump
Holly regulator
Flocsan meter
Fram fuel filter
1/2 inch hoses from pump
Oil Cooler with Mercruiser filter on the firewall
senser on oil filter mount
looks like one wire goes to relay, then to fuel pump

If I run with 3/8 hose into tank it pumps at 1 gal per 40 seconds
If I start the motor it will start, but idles rough like it should, but if I accelerate it conks out like no gas


Is the pump doing the right amount of fuel into the tank?
How many gallons a minute should an engine like this burn? Idle? Full Throttle?
How many RPMs max?
Can I ask more stupicd questions?

Thanks,
Tom

H2Xmark

you need 1/2" line and also check your anti-siphon valve at the fuel tank

Tom

Thanks for the reply.

I do have 1/2 inch line to the carb, just used 3/8 to the storage tank since that was the biggest I could find.

What anti siphon valve? I have a bag up front with big hose going in from frill cap and looks like 1 inch hose coming out to the fuel pump in the back of the boat. Maybe the bag does not have anti siphon in it?

Tom

H2Xmark

most fuel tanks for boats have one, it is put there to prevent in case of a fuel line leak, so the leak will not fill up the bilge, it is a fitting that threads in at the tank and has a barbed end on the other side for the fuel hose to hook to, it has a checkball with a small spring it in, the suction of the fuel pump pulls the ball of its seat letting fuel flow, but if you get a leak on the line with your engine off the pressure in the fuel tank will keep the ball seated shuting off fuel fiow, sometimes these valves get pitted or something else happens to it not giving good fuel flow, it is installed at the fuel outlet of the tank

Tom

Thanks for the advice,
I looked at the fittings coming from the tank and the only one is a clamp fitting where the line comes out of the bag and goes back to the engine. Back in the engine compartment there is a flowscan meter first, then a fitting with a grey ball on top, then the fuel pump, then filter, regulator, carb.

Does that mean you think I am not getting enough flow at 90 gallons per hour from a holly black pump? I assume the 3/8 line is restricting flow, but to the carb is all 1/2 inch. Do you have any idea how to calculate what the flow would be if 1/2 inch?

How many gallons per hour will a 650 horse engine burn at WOT. How about at idle?

Thanks,
Tom

H2Xmark

there was a thread a little while back{1or2weeks ago} on a person who had some of the same issues you have, it was in general discussion's, you might try a search, I think one of his problems was the holley pump was mounted to high, it has to be level with the bottom of the tank to work, electric pumps push very well, but they will lose their prime if mounted to high and give you problems , you might install a fuel pressure gauge at the carb, and have someone watch it{might have to remove hatch}if you lose fuel pressure {below 7or8psi} then you will have to find that fuel flow problem