Fuel vent hose type

[kmelford]

Is there a special type of hose I should use when replacing my gas tank vent hoses? I didn't see any references to these hoses in the fuel system posts.

I have a 1997 bassboat and the hose is connected to each side of the gas tank that comes to a 'T' than to the vent which is part of the fill device. I broke the T when replacing my batteries and it seems the hose is very hard and it cracked on the ends when trying to pull off the old one.

For reference, I have a 1997 Mercury 175 EFI motor (ser number 0G361770)

Thanks.

[massbays]

usually vent hose is 5/8" A1 type hose.

[EuropeanAM]

+1.... may even be Type A1-15, 5/8" ID (usually quite thick OD).

[kmelford]

Thanks guys. I was able to find the faded lettering on the hose and it is 5/8" type A1. Seems like that hose is difficult to find.

[EuropeanAM]

Try type A1-15. That's the new designation for that hose type.

[kmelford]

I'm struggling to find 5/8" Type A1-15 hose. Other sizes are available but not 5/8" (i.e. 3/8 and 5/16). I found 5/8" Type A2 hose which looks to be specifically for fill and vent lines. This hose is only to replace my vent line. Here's a USCG comparison:

USCG Type A1 hoses are designed for fuel feed applications where the fuel is constantly in the hose, whereas Type A2 hoses are designed for fuel fill type hoses only

I've checked a few other sources and the info seems consistent. The difference is related to permeation rate. In my case it's a vent hose and fuel should never be flowing through it. Therefore, I'm thinking of going with the A2 hose based on availability.

Any additional feedback is welcomed.

Thanks again.

[kmelford]

I may have found a source for type A1. They have some remnants they may be able sell me. I will likely go with Type A2 if it doesn't work out.

[EuropeanAM]

A1-15 and A2 are very similar.

[massbays]

I thought A2 had been replaced.
originally A1 for fuel lines that will stay full of fuel and can be run thru engine spaces.
A2 for fuel lines that flow fuel but are usually empty. such as fuel fill hose and vent hose.

[kmelford]

Yes, based on my research type A2 can be used for vent lines and fill lines.

I got lucky and found 5/8” type A1 from a local shop that had some remnants with lengths that worked for me. Thx for the feedback