Fuel line length?

[SilentOption]

No doubt a silly question but...I have a 75 HP Yanmar, I would like to relocate my fuel filters to the aft lazaret which would extend my overall fuel line distance to 16 feet.

Does anyone know if that is or would be an issue.
I am running a mechanical pump only. The one on the engine.

Thanks

[model 10]

I don't think that is a silly question at all. 16' sounds like a lot so I would wonder what size fuel line you would be using. How much lift is a mech pump is happy with? My guess is if this is much of an increase from stock you would use a bigger line.

[Lepke]

16' isn't much more than a large car with a front engine and rear tank. Today's cars have electric pumps, but in the past used lift pumps similar to most boat engines. The fuel line would be best if it was without too many up and down bends that could leave air pockets.
Another option is to add an inline electric pump. I have then on my mains. I use them for priming my filters. They're also handy if your engine has set for some time and there's air in the lines. The fuel flows thru the pump when they're not running and the lift pump is doing the work. They don't bother the lift pump.

[SilentOption]

Thanks.

I think the electric pump would be a good backup anyway.

Bill


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[Emerald Sea]

16ft length in general should not present an issue. If the elevation of the pump is higher than it was in its original position (assuming it is as you are going from eng room to deck) than you need to assure the additional lift can be accommodated by the fuel pumps output pressure. But even a meter height with a 12mm ID hose should be fine. The extra length will have added friction loss but this is likely to be negligible.
Having a spare pump is recommended and if you havent purchased one yet, get one with a slightly higher output pressure.

[SilentOption]

I've been running the engine on the mechanical pump with no issue. I will still put an electric pump inline just for redundancy.


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[model 10]

Originally Posted by SilentOption

I've been running the engine on the mechanical pump with no issue. I will still put an electric pump inline just for redundancy.
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That's good because you will be more likely to need it. An electrical pump adds resistance and the mechanical pump is a lift pump, so you will be making it's life much harder by adding an electrical pump in series.