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Fuel line size question

M

michigander

Member
"Greetings,
Installing a n

"Greetings,
Installing a new 5.7 Crusader Classic which is the carbed model with a 650 Holley. The installation manual calls for the fuel line to be 1/2 I.D. My boats fuel lines are all 3/8 I.D.and would be a real pain to change.The installation manual is rather generic for the 5.7 EFI model and the carbed model.My question is,is the 3/8 fuel line adequate for the fuel demands of this new motor? Surely don't want to cause a lean condition and harm this new motor.
Thanks in advance,
MICHIGANDER"
 
Plenty big enough. My 360s hav

Plenty big enough. My 360s have 3/8 before the pump and 5/16 after it. Came that way.

Jeff
 
"The Garmin fuel sensors that

"The Garmin fuel sensors that can measure 50 gallons an hour use a 3/8 fuel line for their flow measurements....if that means anything. Additionally, my 5500 series floscan also measures up to 50gph and has 3/8 fittings"
 
"MICHIGANDER,

1/2" is c

"MICHIGANDER,

1/2" is certainly recommended. If the run is short, being you are carbed, you can probably get away with 3/8.

EFI engines can not get away with anything smaller than 1/2 since they flow so much more fuel, even though 70% of it is returned to the tank.

If you're replacing a worn out engine, how good are those old fuel lines?

Personally, I would change them. Even if they flow enough, they can become soft and suck flat under a load."
 
"Greetings,
Installed all ne

"Greetings,
Installed all new 3/8 I.D. fuel lines as Rick Suggested (short run). Been having a fuel flow problem a w.o.t.The motor will die as though the key was suddenly turned off.Then will start right back up. As a test (and only a test) I removed the antisyphon valve from one tank.Problem solved on tank w/o antisyphon valve.Runs great at full throttle.Tank with the antisyphon valve the problem remains.Read on this site a statement that "electric fuel pumps don't like antisyphon valves".Do they make high flow antisyphon valves? Or is there an alternative that will meet uscg requirements?
Thanks in advance,
Michigander"
 
I'm using a 3/8 swagelok 1

I'm using a 3/8 swagelok 1/2 psig with my model 350's. I tested up to 3-6 psig and the mechanicals worked fine but the electric pump for my generator wouldn't. Testing the 1/2 psig on a cracked line at the generator since it is below the fuel tanks show no syphon or leakage.
 
"Unless you have lots of stock

"Unless you have lots of stock in Exxon, I'd say you won't be running full throttle all the time, so 3/8 before the pump is fine. And don't make the mistake of adding fine fuel filters BEFORE the fuel pump; after it only.

Jeff"
 
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