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Fuel lines

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tomofficial2

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"I have 1984 twin 270's, f

"I have 1984 twin 270's, fuel line from fuel pumb to carb showing ware, can I install rubber lines or is there a code that requires hard pipe??"
 
"Good question. I replace the

"Good question. I replace the aging copper lines on mine with stainless, but I also have A-1 alcohol resisting marine rubber fuel hoses connecting an in-line fuel filter. Some say this is not USCG approved, but I've seen two cases of metal filter housings that cracked open due to vibration, spraying gas all over the place. Rubber hoses allow for vibration and don't do that.

Jeff"
 
"A TOTALLY Un-related boating

"A TOTALLY Un-related boating thing BUT...JEFF you will appreciate this, That picture of the 1925 Henderson avatar was restored in 1996? When I took it out for its' first ride, I had to fabricate a copper fuel line running from gas tank to carb.

During the 20 minute ride, the copper fuel line cracked from vibration AND unknown to me the leaking fuel caught fire . At 40 miles per hour I did not see or feel the flames ...YET. My friend passed me and we pulled over.

Beat my right leg to put out the flames and then threw sand and dirt on the engine to smother the fire after turning the fuel valve off. TWO YEARS and over $15,000 to restore the thing and it was nearly lost within 20 minutes by a broken copper line. FORTUNATELY no damage even to those 8 exposed valves on the right side. Made a new line from steel brake lines and SOLD the bike to a collector in Switzerland who had seen it in a magazine."
 
"Properly installed, the steel

"Properly installed, the steel line is much more durable. If you use a soft line, make sure it is tolerant of ethanol blends. either will work. The real question is will your insurance still cover you if you use something other than the OEM material."
 
I can't find a reference n

I can't find a reference now to requiring a metal fuel line after the pump. A1 in 3/8" is rated to 50psi and constant fuel exposure.
 
"And most carb setup run at 4

"And most carb setup run at 4 to 6 psi. Sounds good to me, and in-line filters attached with rubber hoses are a breeze to change.

Jeff"
 
"Did some more digging on this

"Did some more digging on this topic - here's what was found:

Several marine surveyors state the line from the fuel pump to the carb must be metal, but they give no reference to substantiate this.

Found a Nigel Calder (sp?) article where he states the CFR requirement for A-1 rated line connecting the pump to the carb. By definition, this includes not only the A-1 rated hose but metal lines.

The last item of interest was ANSI/ABYC H-24. Not being an AB&YC member, I don't have the access information to get to the text, online. BTW, this is a voluntary standard which represents 'best practices'."
 
"That's not it either. In

"That's not it either. In the page you linked to, on the left in the blue section click "fuel hose" when that page opens you will see under the floats a premade flexible fuel line with the ends on it. It works great. "
 
"You're talking about one

"You're talking about one of these:

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flexline"">

Description:

FUEL LINE HOSE For fuel pump to carburetor connection. Replaces copper or steel tubing 3/8" X 31" PTFE composite hose with 5/8"-18 male inverted flare straight one end, 5/8"-90degree one end. SAE J1527 type A1

Yes, looks they they are 'approved' - that what the "TYPE A1" rating is all about.}"
 
"That's an option, but onl

"That's an option, but only if you order the shorter line....then again, there's always that Custom Made FastJeff product..."
 
There wasn't a fuel filter

There wasn't a fuel filter in the steel line it replaces so why do you need one? You have the filter before the pump and the screen at the carb. Do you need more?
 
"What does that equate to? 15,

"What does that equate to? 15,000 gallons of filtered fuel through the system per engine?"
 
"you know, I've never adde

"you know, I've never added it up but i can tell you it has been a lot.....more earlier, in her younger years, when a lot of trolling was done."
 
"That tiny filter in the carb

"That tiny filter in the carb has caused a bunch of burnt pistons. You need a really good sized filter AFTER the fuel pump in these days of "evil-nol" gas. It loves to stir up crud in the bottom of the tank, crud that was happy to just sit there before ethanol came along.

Since even a good sized in-line filter needs periodic replacement, just imagine how easy it is for that tiny carb filter to plug up!

Jeff"
 
Why wouldn't the filter be

Why wouldn't the filter before the pump catch as much crud as the filter after the pump?
 
"According to Racor/Parker, th

"According to Racor/Parker, the best place to put a water seperator is before the pump, since the pump will tend to emulsify the water, making the seperator ineffective.
One could debate the effectiveness of a pressure side filter; For my boat, I keep things simple, and have no secondary filter. Unlike the Qjets, I don't believe that the carters even have a wire screen, although they may have moved it to right near the inlet valves.
In a more complex fuel valving installation, especially with a filter bypass valve and engines with injectors, the secondary filter has some merit. But, in my boat, the idea of two filters in series just means the second one has nothing to do.."
 
"Agree with Dave.

The curre

"Agree with Dave.

The current filter, under the inlet nut, on a marine Q-Jet isn't much more than a nylon mesh screen - very coarse. i've seen many running without it being installed. I believe Jeff's observations regarding these filters are rooted back in the days when they were made of sintered bronze.

Also, I've had my air horn off a few times. There has always been a detectable amount of 'fine crud' at the bottom of the bowl. I believe this is the congealed result of what passes thru the filter.

Bottom line - filters won't catch everything so expect to clean things out once in a while. With the proliferation of ethanol, the frequency will probably increase until the tank(s) become pristine inside."
 
"Here's the deal:

1.

"Here's the deal:

1. You need a water separator STRAINER (coarse, 30 micron filtration) before the pump, to protect it.

2. You need a fine FILTER (10 microns) AFTER the fuel pump to protect the carb.

If you have a FINE 10 micron filter before the fuel pump, and if you get get a load of crappy gas, you'll end up with a plugged filter, gas starvation, and holes that will magically appear in your pistons!

I know that some people 'get away' with it--some boats even came from the factory that way--but it's Russian Roulette with 5 bullets in the chamber.

Jeff"
 
What 'stuff' will the

What 'stuff' will the 10 micron filter 'protect' the carb from? I know those internal passages in a carb get small but nothing I seen gets anywhere close to 500 microns.
 
"Fine dust in the gas.

Jef

"Fine dust in the gas.

Jeff

PS: The micron filter scale works assbackwards: A bigger number equals less filtration, hence a 10 micron filter is much finer than a 30."
 
"Fastjeff,

I was rereading

"Fastjeff,

I was rereading this post and had a question. regardless if the filter is before the pump or after if it plugs up you are going to starve the engine. So you are saying that after the pump it will prevent burned pistons. What makes the differance? I am not doubting you but always trying to learn. Have a good weekend."
 
"Good question: The fuel pump

"Good question: The fuel pump can only "suck" a few psi before the fuel flashes and pumping ceases. After the pump, however, it puts out up to 6 or 7 psi. Which would you want pushing past crud in a filter!

Jeff"
 
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