Supply Fuel Line Lehman 135

I have a small leak in the supply fuel line to the lift pump on the port side engine. There is what looks like a 3/8 hose running from the racor filter case to attached to a two foot braided line that attaches to the lift pump underside. I have two questions. I assume the braided to rubber hose fitting is barbed it has a hose clamp on it and maybe the source of the leak.

When I disconnect the braided line will the fuel from the fuel filters come out?

What fitting is this that goes into the bottom of the lift pump? I might need a new braided line made.

My P90 had a braided line from the fuel pump output to the CAV filter. Cu line from tank to fuel pump inlet. When braided line developed a leak, I purchased barbed fittings, and replaced all fuel lines with rubber.

Rubber is easier to inspect for deterioration, inexpensive, and easier to install. Yes, some fuel will spill, put a small al baking pan under CAV filters and a few paper towels. You will need to bleed the CAV filters prior to starting.

Depending on the relative fuel level in your tank it may keep running out. Before disconnecting anything turn off the tank valve to avoid this possibility.

Rubber fuel lines will burn thru faster than braided, if that's a concern.


The "best" is steel or copper fuel lines with a short braided section to the engine to allow it to dance..

Contact American Diesel. They have the knowledge and the parts.

https://americandieselcorp.com/

FF said:

Rubber fuel lines will burn thru faster than braided, if that's a concern.


The "best" is steel or copper fuel lines with a short braided section to the engine to allow it to dance..

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This is some very good advice that FF
Guru gave you.

Thanks for the advice, due to the tank being up higher than the bottom section of the braided line it was still leaking when the engine wasn't running so I turned the valve off yesterday. i have no idea how I am going to get the hose off or for that mater ever change the lift pump the oil cooler is right there in front of everything.

FF said:

Rubber fuel lines will burn thru faster than braided, if that's a concern.The "best" is steel or copper fuel lines with a short braided section to the engine to allow it to dance..

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Rubber is rated for 275F. Metal braid for 350F. Your block is not running anywhere near 275. You will be boiling over by 250.

Metal braid is typically used in high pressure applications or in locations where abrasion is likely. Lehman ran a short length of hose behind everything creating an abrasion risk. I ran mine outside and used loose tie wraps to secure it.

It is easier to just remove any oil coolers or heat exchangers to allow access to fuel pump. Good opportunity to clean them out and replace cooling hoses. Not a lot of room to swing a wrench.

If you have an engine room fire that is already threatening your fuel lines long enough to burn through the rubber, it is likely that the boat is already a goner.

So I take it rubber is ok as long as it's coast guard approved fuel line and not touching anything.

Real, approved fuel line is very beefy and you'll be glad you did. Don't understand the comment about it not touching anything?

Ken

i meant rubbing on something that will make it wear prematurely.

Derik said:

So I take it rubber is ok as long as it's coast guard approved fuel line and not touching anything.

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Hose for marine usage must be stamped with "USCG type a1-15." Would become an issue if you required a survey.

I used rubber cushioned st stl clamps to secure hose along stringers.

"If you have an engine room fire that is already threatening your fuel lines long enough to burn through the rubber, it is likely that the boat is already a goner."

UNLESS you have treated your boat to a remote operating fuel cut off valve (push pull cable to outside) from the fuel tank, as found on commercial vessels.

Pretty cheap insurance.......Probably under 1/10 of a boat buck per engine.

FF said:

"If you have an engine room fire that is already threatening your fuel lines long enough to burn through the rubber, it is likely that the boat is already a goner."

UNLESS you have treated your boat to a remote operating fuel cut off valve (push pull cable to outside) from the fuel tank, as found on commercial vessels.

Pretty cheap insurance.......Probably under 1/10 of a boat buck per engine.

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ER fires haven’t been a huge worry for me but reducing the risk is another reason I like running from the day tank. Shutoff valves for the active fuel supply are in the aft cabin—where the day tank is located—and it can be quickly isolated. All of the saddle tank valves remain closed except during fuel transfers. Which reminds me—I need to start a thread about rebuilding our fuel transfer system.

If contact wear cannot be readily avoided then protect those areas with a short length of hose split and Tywrapped into place or use some of the corrugated overwrap for electrical.

Lots of different ways to provide wear point protection.

As far as access to the lift pump and the hose you may need to move the cooler. If there is enough hose slack you may be able to just free it and then hang it out of the way. If not then remove it but just be prepared to deal with the coolant and the oil contained. You may have to lower the engine coolant so you don't get a gusher. In fact since most engine oil coolers are coolant cooled simply drain the engine.
American Diesel whould be able to tell you if draining coolant will be needed.

If you don't call them then assume you will need to drain the coolant. You should be able to reinstall it if the stuff is recent.