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Fuel Line Feed Requirements 38 vs 12

knuckle47

knuckle47

Advanced Contributor
"My friend and I have the same

"My friend and I have the same boat... They were actually made 1 serial number apart 25 plus years ago. His re-power is with 454XL's and mine with 454 regular ( If thats the right nomenclature). He tells me is is currently running 3/8 fuel lines as am I however his books tell him he requires the 1/2 instead. BOTH of our boats use carburetors. I have added the Garmin GFS 10 fuel sensors to the boat which have 3/8 fittings...No flow issues I presume.

IF IF, he changes the fuel lines to 1/2" how will the reduced 3/8 fitting of the Garmin sensors affect fuel flow ?

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fuel screen
 
"Ayuh,... Hi Al,...

I have

"Ayuh,... Hi Al,...

I have to think that 3/8" lines are more than enough to feed a 454 carbed motor....

I'd put it together the way it was,+ Run it...

If by some slim chance it exibits a Lean condition,...
I'll be proved Wrong,...
But,...
I Doubt that'll happen..."
 
"it will add a minor pressure

"it will add a minor pressure drop to the line that should be insignificant. if the existing 3/8" line is ok, there shouldn't be any reduction in flow capability going to the new setup as long as it is a fairly straight shot."
 
"Food for thought
I've s

"Food for thought
I've seen simulated fluid flow within hose / tubing. Imperfections in the walls cause eddie like disturbances (restriction). Naturally, the longer the tube / hose, the more restrictions, & flow is diminished.
Things are not so bad IF the pump is near the tank, & the fluid is pushed; but the system suffers, IF the pump is near the Engine, (pumps inherently, push better than they draw).

A 3/8 restriction in the over all length of the path of flow will be insignificant as compared to a complete 3/8 I.D. fuel system.

I never thought about it, but one could "T" in a vacuum gauge (some semi tractors have a gauge labeled fuel filter restriction) near the draw side of the pump, then dig for a spec on the pump.( I'm sure that the gauge would be calibrated in , inches of water, as opposed to inches of mercury).
I think the correct spec. term may be "head", as in a home well pump has a maximum of "10 foot head" (it will lift water 10 feet)."
 
"Should work fine UNLESS you&#

"Should work fine UNLESS you're an ocean racer. Cruising speed is the thing nowadays, right?

Jeff"
 
"I agree Jeff
If it need mor

"I agree Jeff
If it need more fuel than your 3/8 line will provide, then you better find the hole.

Fred 156-M"
 
"fred:

racor has sold liqui

"fred:

racor has sold liquid filled gauges for decades for their filters. Last time i looked, they were in "inHG".

When it comes to pumps, "head" is the vertical distance they 'push' and "lift" is the vertical distance they 'pull'. They few charts I've seen are all for electric pumps and they fall off gradually with either, at least for the ranges one would see on a boat."
 
"I have the same setup. I ins

"I have the same setup. I installed the Garmin fuel flow sensors (GFS10) in both engines and they work great. No engine problems at all even at WOT (25 GPH/engine)

The reason they are 1/2" is because you can use one tank to run both engines (50 GPH) plus the generator using the fuel switches to direct flow from one tank. To balance tanks.
I don't see me ever doing this, so not a problem."
 
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