Fuel filter location

[rdempsey]

My fuel filter is located in the cockpit locker with the drain only half an inch from the hull. Hard to get at and impossible to drain!

I plan to relocate it, but was wondering about how high above the fuel tank I can place it without causing problems.
Engine is a Yanmar 2GM20F.

[Vasco]

Had the same problem with a Racor, used too drain it into a frisbee.

[swagman]

The reason they site filters lower than the tank is to prevent back flow when the filter is opened.
So if you do relocate so its above the tank, then ensure you put a stopcock on the tank side of the filter and close it before opening filter, or consider inserting a small pump into the fuel line twix tank and filter.
Cheers
JOHN

[S/V Illusion]

although you can mount it above the fuel level, it makes life a little easier of it is gravity fed so moving it up a bit for easier access won't hurt anything.

[delmarrey]

Personally, if it has a tranaparent bulb, I would move it to a spot where it can be easily seen and accessed. And down close to the tank if possible.

If you were ever to loose the seal on a fuel line. You would be getting air into the fuel line causing running problems. It's best to have the shortest run between the tank and motor with the filter slightly above or level with the fuel tank. If it's too low the fuel will sophon out during a filter change, unless you add a shut of valve.

If you look at all the big trucks out there you will find the filters monted slightly above the tanks.

On mine I've even installed an electric fuel pump, with a switch valve and fittings, between the tank and filter to prime the motor and system after a filter change or if I ever run out of fuel
..............................._/)

[never monday]

Originally Posted by swagman

The reason they site filters lower than the tank is to prevent back flow when the filter is opened.
So if you do relocate so its above the tank, then ensure you put a stopcock on the tank side of the filter and close it before opening filter, or consider inserting a small pump into the fuel line twix tank and filter.
Cheers
JOHN

I must dispute this and clarify.
The filter should be mounted in a place most easily accessed for service.

When you mount a filter below the tank, gravity and siphon will overflow the filter when it's opened unless you have and use a valve at the tank. A valve is required under ABYC. The valve shall be mounted to the tank and not the filter.
Small pumps should not be mounted where they would create positive pressure in the filter housing. The filter is designed to be used in a vacuum and has internal check valves to allow prime to be maintained.

[Ex-Calif]

You mount it below the fuel level in the tank and the fuel drains when the filter is open.

You mount it above the fuel level in the tank and fuel drains back to the tank allowing air in when the filter is opened.

Either way a stopcock fixes that.

I would be wary of mounting it too high above the fuel pump. The pump has to be able to lift the fuel from the tank, through the filter, to the inlet.

[David M]

It's always a good idea to have a shutoff valve on the fuel tank on both the feed and the return side. An even better idea is to have a cable on the handles which allow you to shut down the fuel lines from up on deck in case of a fire. You are totally screwed if a fire starts down there and you cannot get down there to shut down the fuel source. Better hope you have a really good CO2 bottle with a remote pull on deck if that happens.

I also have a valve at in the inlet and outlet side of the filters so I do not introduce much air into the lines and so that there is very little spilled diesel when changing the filter elements.

I prefer having the filters below the top of the diesel level in the tank because diesel will siphon into the filters displacing most of the air right after doing a filter change.

[delmarrey]

Originally Posted by never monday

A valve is required under ABYC. The valve shall be mounted to the tank and not the filter.
Small pumps should not be mounted where they would create positive pressure in the filter housing. The filter is designed to be used in a vacuum and has internal check valves to allow prime to be maintained.

Good point!

I need to check system again. BTW what ABYC reference code # is showing a required valve. But a good idea, just like in hydraulics............................_/)

[never monday]

Just a dumb question for my own knowledge...

Why do you guys build these elaborate systems with multiple potential failure points to alleviate the need to bleed the system?

Why not just get comfortable with bleeding it?

it just the more I learn about boats, the more I want mine on the K.I.S.S. principal.

[sildene]

Originally Posted by never monday

Small pumps should not be mounted where they would create positive pressure in the filter housing. The filter is designed to be used in a vacuum and has internal check valves to allow prime to be maintained.

Pat, good point of which I had been unaware. In contrast to the primary "rough" filter, I assume that the engine "fine" filter is designed to handle modest positive pressure, since it is normally downstream of the engine's mechanical lift pump.

So, if I want to add an electric fuel pump (5psi on a 3-cyl inboard) to be able to circulate diesel from one tank to another while filtering the fuel, it should not be located between tank and primary filter, but rather between primary filter and engine fine filter (suck through primary but push through engine filter, y-valve after engine filter)?

Martin

[delmarrey]

Originally Posted by never monday

Just a dumb question for my own knowledge...

Why do you guys build these elaborate systems with multiple potential failure points to alleviate the need to bleed the system?

Why not just get comfortable with bleeding it?

it just the more I learn about boats, the more I want mine on the K.I.S.S. principal.

I wouldn't like dumping fuel all over my nice clean motor, plus if there is any air in the lines it can be purged out with little effort.

One thing that's different about my 27 YO boat is it doesn't smell like diesel when you go below. It's clean and sealed and it's going to stay that way.

[Steve Pope]

I have my filters around a metre + above the tank which is in the keel, to assist with bleeding and filter changes I have fitted a primer bulb, the same as used on outboard motor fuel lines. As it has a non return valve in it you don't have a problem with the diesel draining back to the tank and it makes bleeding a breeze. Cheap too!

[never monday]

Originally Posted by sildene

So, if I want to add an electric fuel pump (5psi on a 3-cyl inboard) to be able to circulate diesel from one tank to another while filtering the fuel, it should not be located between tank and primary filter, but rather between primary filter and engine fine filter (suck through primary but push through engine filter, y-valve after engine filter)?

Martin

Martin,
You're correct. My only word of caution is, if you have a mechanical lift pump. Becareful using the electric to feed the engine. If the diaphragm is cut, you can fill the engine with fuel.

[drh1965]

Originally Posted by never monday

Just a dumb question for my own knowledge...

Why do you guys build these elaborate systems with multiple potential failure points to alleviate the need to bleed the system?

Why not just get comfortable with bleeding it?

it just the more I learn about boats, the more I want mine on the K.I.S.S. principal.

I can't speak for everyone but for me, bleeding is the single most messy, frustrating chore I have to do on my boat. It is also not a deterministic process. There is no way to be 100% sure all the air is out before cranking. If not, the air migrates from areas that bleed fairly easy (primary fuel filter, lift pump and secondary filter) to areas that don't (the injection pump). At least, that is how it happens to me.

FWIW!