Yanmar 3GM30F Fuel Pump - For decoration only?

[ianybw]

Hi,

I have a Yanmar Diesel 3GM30F. It runs and starts fine. I also have an electric fuel pump controlled by a on/off switch in the engine compartment. I turn the switch on the pump runs fine, so I just turn it off again.

I start the engine by giving it some throttle, cranking it over and it starts fine.

My question is, whats the electric fuel pump for? Am I supposed to use it for priming the engine or something?

I cant believe its just there for decoration?

Thanks In advance

 

[wotayottie]

cant imagine what its there for. the yanmar pump will suck up fuel as necessary and you certainly dont "prime" a diesel engine.

could it be the pump for the diesel powered heating? or could it be the pump for water circulation?

best ask the previous owner

 

[lydiamight]

Probably installed to make priming the system easier after you have changed the fuel filters. Just open the bleed screw on the top of the fuel filter, turn on the pump and wait for clear (no bubbles) fuel to flow. Damn sight easier than fiddling about with the small lever on the fuel pump.

 

[ianybw]

Thanks for the reply, it has no heating system ( as yet ), so I suspect it is for bleeding the system.

Runs fine otherwise, if it isn't broken I wont fix it.

Thx

 

[david_bagshaw]

is the fuel tank well below the engine? the extra pump might be to help lift fuel when the tank is nearly empty.

 

[ianybw]

Another excellent idea, but its about at mid-height, so dont think its for that.

Oh well, its just something else to switch on and off again several times when the engine wont start one winters morning.

Thanks

 

[Gunfleet]

You're sure there's not a day tank? That can be topped up by a little pump.

 

[mcc2905]

I have installed a switch operated electric pump in the fuel supply line on my 3HM35F's, specifically for bleeding the fuel system as the fuel level may be as much as 3 feet below the mechanical engine pump. I was finding it virtually impossible to pump/beed fuel through after replacing the fuel lines and have only found the electric pump necessary for this purpose, when properly bled the engine runs fine using just the mechanical engine pump.

 

[ianybw]

A day tank? I dont think so, if there is a tank its well hidden and unused, there isnt a heater on the boat. Thats next years project.

 

[snowleopard]

I have an agglomerator (water separator) between the tank and the engine lift pump. When starting from an empty system it took ages to suck out a pint or more of air in order to fill the fuel line with diesel by using just the lever on the lift pump. I fitted a rubber priming bulb (taken from a diesel car) to pull the fuel through as it's cheaper and more reliable than an electric pump.

 

[Salty John]

I'd say it is almost certainly there to make bleeding the fuel system easier; it can be a pain with that little lever under the mechanical pump.

 

[tugboat]

sylvesterthecat & mcc2905............. I need to fit a pump into my system for bleeding after filter change. Please can you tell me what pump you have. Is it an automotive unit or designed for marine use. Must be intended for diesel as must be nitrile bits inside. Thanks.

 

[mcc2905]

This web address "http://www.fuelsystem.co.uk/web-facet.pdf" will download a PDF catalogue of Facet pumps, I originally used the Solid State Pump SS503 to prove the theory but these went rather rusty so when one failed I replaced with the Posi-Flow Pump 60106. They are suitable for diesel and can be left inline and used only for bleeding, it makes the whole job quick and simple.