Electric fuel pump

Jul 2, 2019
102
Hunter 310 Pine Beach, NJ
Yan 2gm20f on a hunter 310.
Manual Makes no mention of an electric fuel pump from the tank feedline. This is an in-line pump before the separator. Question is can I safely assume this is a positive pressure pump and when I crack the line down stream fuel won’t just keep running? I cannot find a valve upstream of the pump and need to be confident that the pump will stop the flow when not energized. If there is a valve the cockpit floor Hass to come up.
 
Feb 27, 2004
172
Hunter 335 North East, MD
I believe that an electric fuel pump is an option installed by the previous owner and I have certainly never seen a yanmar manual which shows an electric pump- your fuel tank should have an on and off petcock-mine is awkward to get to but I do switch off before I change my primary filter
 
Jan 7, 2011
4,727
Oday 322 East Chicago, IN
I agree, probably a PO modification, the 2GM20 has a mechanical pump mounted on the engine. Apparently if the diaphragm leaks, an electric fuel pump is a common modification.

Can you trace the fuel line where it comes out of the tank? On my O’Day 322, the shut off valve is within inches of the tank.

Greg
 
Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
Google is your friend, so learn to use it. Credits to @Stu Jackson .

Speaking as an H-310 owner from new, the electric pump was installed by the previous owner. Get the ID off the pump and search for it on the net. I installed this one in my fuel system after one too many hassles with my cam operated fuel pump:


Fuel Filter and Lift pump R.jpg

If your elec. pump is the correct selection, it will NOT shut off the gravity flow of fuel with no power. This allows your engine to pull fuel even if the elec. pump fails during operation. The isolation valve before the filter means you never have to go back to the tank when working on the filter, pump, or whatever you've got in there.
 
Jan 19, 2010
1,169
Catalina 34 Casco Bay
Your fuel system should have a 90 degree valve on the tank outlet. This allows you to shunt the fuel flow during any service work..
if you have an electric pump it should be heard when the ignition key is in the on position. BUT, it will not be heard if there is sufficient pressure, as it ramps up and or down depending on the need.
 
Nov 22, 2011
1,192
Ericson 26-2 San Pedro, CA
I agree, probably a PO modification, the 2GM20 has a mechanical pump mounted on the engine. Apparently if the diaphragm leaks, an electric fuel pump is a common modification.
On my 1GM I installed an electric fuel pump BEFORE it decided to leak! Plus, I've also plumbed it with a switch in the engine compartment so now bleeding the engine after changing filters is a breeze.
 
Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
BUT, it will not be heard if there is sufficient pressure, as it ramps up and or down depending on the need.
...................... which depends on the make of the pump. The Facet Cube pumps runs at a constant speed and bypasses fuel to control the pressure.

Fuel Pump specs.JPG
 
Oct 22, 2014
20,995
CAL 35 Cruiser #21 moored EVERETT WA
Ralph.
What about the Facet statement “Do not use on fuel injected vehicles”?

Does the pump provide a bypass if the pump is off?
 
Jul 2, 2019
102
Hunter 310 Pine Beach, NJ
Ralph.
What about the Facet statement “Do not use on fuel injected vehicles”?

Does the pump provide a bypass if the pump is off?
My pump (don't know the make or model yet) behaves like is has a bypass or can freewheel forward with no resistance. If I crack the line downstream, fuel keeps flowing.
 
Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
What about the Facet statement “Do not use on fuel injected vehicles”?
According to the Yanmar dealer here in Vancouver, they've been installing them in boats for years. I bought it from them on their recommendation and never seen a hiccup since. Go figure.

Does the pump provide a bypass if the pump is off?
When the ignition key is first turned on, the HP diesel pump is dead ended (OFF) and the pump continues to click away. Got to be a by-pass or else something in there is not too, too, insistant with its stroke:rolleyes:. I remember leaving it running with a stopped engine for several minutes when I first installed it to make sure it had no problem dead ending. No overheating, nada.

Not a clue as to what it means "not to use on a fuel injected engine." Does it make any difference if the engine is carbeuretted ? ? ? ? The fuel pump is still dead ended if you sit there without starting the engine.
 
Jul 2, 2019
102
Hunter 310 Pine Beach, NJ
Not a clue as to what it means "not to use on a fuel injected engine." Does it make any difference if the engine is carbeuretted ? ? ? ? The fuel pump is still dead ended if you sit there without starting the engine.
Only thing I can think of is many gasoline FI systems run the fuel in a loop. Whatever pressure is above regulator pressure is looped back to the tank. This type of system would make a lift pump run at full volume constantly and maybe that would make their pump unhappy.
 
Jan 30, 2012
1,123
Nor'Sea 27 "Kiwanda" Portland/ Anacortes
Unsure exactly your symptoms. Maybe how it works will help in your diagnosis.

In these systems the motor mounted fuel pump (or the electrical fuel pump if that is how your system is designed) are called lift pumps. That means they just suck fuel from the fuel tank (at maybe about 6 psi) -- via the motor mounted fuel filter canister -- and thence to the the high pressure pump intake.

At that point the high pressure pump compresses the fuel and delivers the fuel to the injectors (from 6 psi at the intake to about 2350 psi output).

The central point is that the lift pump output pressure (4-6 psi) has nothing to do with the 2300 + psi gets delivered to the injectors.

As to feed line - any fuel tube/hose feeding the lift pump (no matter fuel inj. or carburetor rated) will do because that line it is under low vacuum.

As to stopping -shutting down - diesel motors (Yanmar included) that depends on setting the fuel shut off cable link such that it cuts of the fuel supply. If the shut off is not cable - electrical instead - verify that the electrical solenoid shuts off the fuel supply.

Charles
 
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Nov 6, 2006
9,885
Hunter 34 Mandeville Louisiana
The Facet wording to not use on fuel injected engines is about gasoline electronic fuel injected engines where the required fuel pressure is a lot higher than the Facet produces.. A diesel only needs fuel to be delivered at a slight positive pressure at the HP pump to function.. The Facet makes enough pressure for that.
 
Jul 2, 2019
102
Hunter 310 Pine Beach, NJ
Unsure exactly your symptoms. Maybe how it works will help in your diagnosis...
Charles
Thanks Charles. I think my post may have not been clear as to motives. I have no symptons and I understand the diesel fuel system. For me this started when I wanted to drain the separator and change the primary. I could not locate the shut off valve and tried to just loosen the filter with the shutoff open, hoping there was not a bypass (or one way flow) through the elec. pump. When it kept draining more than I thought it should, I posted, asking about these specific characteristics of a marine diesel elec. fuel pump.