Stainless Steel Hose Clamps on Fuel Lines

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
Jefecinco
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Stainless Steel Hose Clamps on Fuel Lines

Postby Jefecinco » Wed Apr 13, 2022 10:19 am

Is there any reason NOT to replace wire-tie clamps [perhaps means nylon cable ties] with stainless steel hose clamp on fuel hoses?

BACKSTORY: Preparing to launch my Sport 13 I noticed fuel stains and spilled fuel on the deck. The fuel was coming from the primer bulb connections to the fuel hose. I was surprised because our local Mercury shop replaced the fuel hose than a year ago during some repair work.

Close examination revealed the leak was on the tank side of the fuel hose. Two things appear to have been contributory. First, the line is clamped to the bulb by a wire-tie and second, the tank was under pressure caused by fuel vapors.

I released the tank pressure and the leak stopped. After cleaning the spilled fuel I loosened the tank fill cap to prevent any tank pressure from building. The boat is stored in our garage which can become hot even during cool weather. The outside temperature was about 70-degrees-F. The garage temperature was about 83-degrees-F. I believe that the tank pressure relief threshold is too high for the fuel line to withstand. Either the tank pressure relief or the fuel line is defective. Due to the wire-tie connection my money is on a defective fuel line.
Butch

Oldslowandugly
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Re: Stainless Steel Hose Clamps on Fuel Lines

Postby Oldslowandugly » Wed Apr 13, 2022 10:36 am

I use stainless steel hose clamps on everything, especially fuel lines. The little plastic tie wraps OMC used from the factory are OK until you touch them and then they are useless. The stainless clamp used on fuel lines usually is OK until it is not. Then I replace with stainless hose clamps. As for the gas tank isn't there a pressure relief built into the gas cap? Usually a small screw valve. It is supposed to be opened so the tank can breath other wise fuel can't flow. I know that storing a gas tank without opening the relief results in great pressure being built up as the temperature rises.

EDIT: Is this a new [portable gasoline fuel] tank?

Attwood 8803LP2 EPA and CARB Certified 3-Gallon Portable Marine Boat Fuel Tank

I just saw that new regulations require a non-venting [portable gasoline fuel] tank, and that means pressure can build up under normal conditions and overwhelm the fuel system. An Attwood 9300FDV7 Universal Fuel Demand Valve for 3/8-Inch and 5/16-Inch Fuel Hoses can prevent [build up of pressure in a portable gasoline fuel tank].

I don't think [awareness of new EPA portable fuel tank regulations enacted in 2009] is common knowledge. I think even with a Universal Fuel Demand Valve, a bulging fuel tank will occur; hose clamps are going to become more important than ever.

Apparently the pressure increase was factored into the design of the tank. The clamps are the weakest link.
Last edited by Oldslowandugly on Wed Apr 13, 2022 10:49 am, edited 2 times in total.

jimh
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Re: Stainless Steel Hose Clamps on Fuel Lines

Postby jimh » Wed Apr 13, 2022 10:43 am

I have seen nylon tie-wraps used as fuel hose clamps, but the nylon tie-wraps intended for that purpose are not the same as run-of-the-mill nylon cable ties. Nylon clamps for fuel hoses usually have a ratchet head mechanism with a rounded side intended to fit better to the circumference of a rubber hose.

For use at the in-line primer bulb, a fuel-hose-style nylon clamp may be preferred over a stainless steel band with worm-screw-tightening-mechanism clamp because of the reduced size and elimination of exposed steel clamp material, which could cause a cut to the hand of someone squeezing the primer bulb.

Also, at the primer bulb, only so much pressure can be applied before the plastic hose barb of the primer bulb would be damaged.

A better steel hose clamp choice is a one-time-use steel band, sold under one branding as an Oetiker clamp. These clamps are often used in OEM assembly of fuel hoses, particularly by Evinrude. For some prior discussion of Oetiker clamps see

OETIKER CLAMPS
https://continuouswave.com/forum/viewtopic.php?t=622

A very handy source of clamps similar to the Oetiker clamps is HOME DEPOT. They generally carry steel clamps intended for use with PEX plastic water hose installation. Here is a link to a HOME DEPOT search page result:

https://www.homedepot.com/s/PEX%2520Bar ... amp?NCNI-5

The advantage of the Oetiker clamp is smaller size, less weight, faster assembly, lower cost, better resistance to loosening, less damage to the hose, more uniform pressure distribution, more consistency in manufacturing. And they were invented in Switzerland, therefore the Swiss Watch of hose clamps.

The drawback to using an Oetiker clamp is the one-time use, the need to correctly size the clamp as the amount of size change is limited, and the need for a specialized tool to close the clamp.

Another excellent choice is the nylon ratcheting hose clamp, which can also be released if desired. They are available in many sizes. Their appearance is shown below:

clamp_.png
FIG. 1. A nylon hose clamp with ratchet mechanism.
clamp_.png (10.06 KiB) Viewed 2027 times

jimh
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Re: Stainless Steel Hose Clamps on Fuel Lines

Postby jimh » Wed Apr 13, 2022 10:53 am

ASIDE: The federal government Environmental Protection Agency [EPA] in 2009 promulgated regulations about portable marine fuel tanks which places restrictions on the use of open-venting of the fuel tank to the atmosphere. For up-to-date information on EPA regulations as given in the Code of Federal Regulations, see 40 CFR 59

https://www.law.cornell.edu/cfr/text/40/part-59

dtmackey
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Re: Stainless Steel Hose Clamps on Fuel Lines

Postby dtmackey » Wed Apr 13, 2022 1:58 pm

Over the years I've repaired plenty of engines where owners have used worm drive hose clamps and the biggest concern I've seen is the wrong size being used and/or over tightening. Either of these can cause hose failure and/or leaks.

The code for clamps on boats:

§ 183.532 Clips, straps, and hose clamps.
(a) Each clip, strap, and hose clamp must:

(1) Be made from a corrosion resistant material; and

(2) Not cut or abrade the fuel line.

(b) If tested in accordance with the fire test under § 183.590, a hose clamp installed on a fuel line system requiring metallic fuel lines or “USCG Type A1” hose must not separate under a one pound tensile force.


Personally, I do not use worm drive hose clamps on ANY gas or fuel line and use Oetiker clamps as they are better and support with equal clamping force around the entire hose without a "cutting" under the worm drive houseing. It is also interesting to note that engine manufactures do not use hose clamps (the worm drive type) on fuel lines for the reasons I've mentioned.

Here is an interesting link regarding fuel line clamps.

https://www.cafsti.org/wp-content/uploads/Hose-Clamps-andFluid-Leaks.pdf

I won't argue that a hose clamp is better than nothing, but clamp type is also an important factor.

D-

Jefecinco
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Re: Stainless Steel Hose Clamps on Fuel Lines

Postby Jefecinco » Thu Apr 14, 2022 12:43 pm

Thank you for the very useful replies. To answer Old Slow's question, the tank is the new type EPA approved six gallon tank.

I have decided to use the Oeticker clamp. Now I need to make sure I get the right size clamps. While I am repairing the leak I'll replace the other three stainless steel worm screw clamps.
Butch

dtmackey
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Re: Stainless Steel Hose Clamps on Fuel Lines

Postby dtmackey » Thu Apr 14, 2022 5:56 pm

Jefecinco wrote:Thank you for the very useful replies. To answer Old Slow's question, the tank is the new type EPA approved six gallon tank.

I have decided to use the Oeticker clamp. Now I need to make sure I get the right size clamps. While I am repairing the leak I'll replace the other three stainless steel worm screw clamps.


Hi Butch,

You can use a simple pair of end cut pliers to squeeze the ear on the clamp and it works fine.

Image

Evinrude would sell the clamps for several dollars each, but if you buy from a beer tap supplier (I buy in bulk) they run about $0.25 - $0.39 each. Here's a link.

https://www.kegoutlet.com/oetiker-clamps.html

D-

jimh
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Re: Stainless Steel Hose Clamps on Fuel Lines

Postby jimh » Thu Apr 14, 2022 6:01 pm

Remember, the guy who dies with the largest collection of tools, wins.

Jefecinco
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Joined: Fri Oct 09, 2015 6:35 pm
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Re: Stainless Steel Hose Clamps on Fuel Lines

Postby Jefecinco » Fri Apr 15, 2022 10:37 am

Thanks for the advice and link.
Butch