diesel fuel line question

[alpha]

yanmar 6lp

fuel tank supply line fitting has check valve,is this necessary?

I think this check valve is restricting my flow

[beamishken]

Was the boat previously petrol & re engined with diesel? I re engined mine and found I had to remove the check valve and it's not been a problem
It's a closed system so shouldn't siphon back unless there is an air leak somewhere

[yam man]

Also is it American boat

[ShinyShoe]

Originally Posted by yam man

Also is it American boat

does fluid dynamics work differently in the US?

[willk]

Originally Posted by ShinyShoe

does fluid dynamics work differently in the US?

No

That said, yam man is an inboard diesel specialist and you are a pill dispenser - so I know who I'm listening to here....

[alpha]

Boat has always been diesel.

American boat yes.

What is the reason for this check valve ?

Thanks for the help guys.

[yam man]

Ok your Learn something here Most American built petrol boats have to have a check valve on fuel tank spigot .

American coast guard state this . if the fuel hose ever split it won't syphon it self or a fire in the engine compartment it can't feed the fire with fuel.

I would do away with the check valve on a diesel more chance of a restriction. As said
Most common on American vessels

[willk]

Originally Posted by alpha

What is the reason for this check valve ?

Used where the engine is higher than the fuel tank. When the fuel pump is not running, some systems may allow fuel to run back to the tank, causing slow starting or possible damage to fuel pumps??

AFAIK, the check valve is a non-return valve to combat the above. It is bound to restrict flow a little. So would a slightly clogged fuel filter, a filter that is too fine a mesh or simply too many filters in-line. See also crushed fuel pipe, clogged lift pipe etc. What have you tested so far?

[beamishken]

I assumed mine had the check valves because it was previously petrol but it's also a US boat
I've seen the check valves choked with crud around tge ball as it acts a little like a filter but with only a small area to get blocked. drillings from plastic tank installation are a favourite

[alpha]

boat engine was running ruff WOT,filter vacuum gauge way up in red.

changed filters no luck.

remove check valve, engine runs like a champ.

check valve did have some crap in it .

would rather have crap hitting filter, so no more check valve

thanks for the help guys.