Tank Vent 21 SLXP

[Luvsthelake]

We have a 2017 Bennington 21 SLXP and the fuel tank does not vent. This is evidenced by the boat running rough then stalling and not starting until the fuel tank cap is partially opened to relieve the vacuum on the system. The boat has 124 hours and is equipped with a Yamaha 150 hp outboard. I have searched the boat and the internet to find where the tank vent is located. The only thing I have found is something that may be a vent attached to the right side of the fill port inside the rear storage/ privacy area (see 1st pic). Importunely, it appears to be nearly impossible to remove. There are two lines going to this device – one form the carbon canister and one form the tank see 2nd pic). Could you please confirm if this is the tank vent and/or if there is another tank vent somewhere else? Also, if this is the only tank vent I would appreciate any advice you can provide with respect to how it can be removed.

William M Fleming PE

 

[Lay Lake]

In the 2nd picture you can see part of the charcoal canister (black and white piece) that goes down to a fitting that is screwed to the floor. Try removing the line that is attached to the canister at the filler neck and the 2 screws that hold the line to the floor. The fitting at the floor has a screen in it. Check to make sure it is clean and then try blowing through the line from the end where it attached to the filler neck. You should be able to blow through it easily. If it is clean and has no obstructions, then remove the other line (it is the same sized line) that is right by it on the filler neck. Try blowing through it to make sure it has nothing in it. Just make sure you don't suck air back through any of those lines. Gas vapors don't taste good.

 

[Potomacbassin’]

Good advice from Lay Lake.

Fuel issues while running - check the vent lines with the canister (tank vent). This is your make up air so the obstruction is either crud in the canister, filter/screen or water collecting in an unintended p-trap. Other thing that can happen is depending on how this is routed, some owners have experienced this vent sucking in water while running and introducing into the fuel tank.

Fuel filling issues - check the fuel fill vent line. Again it seems the most common cause is an unintended kink that forms a p-trap and over time collects fuel.

 

[Luvsthelake]

Thanks, Lay Lake! I'm changing the oil right now then I'm putting on some "chap stick" checking out the vent! I'll let you know how it works.

 

[jcbecker28]

Well, did you find the problem?

 

[Steelbreeze]

Just had my vent moved by dealer as the source of water ingress we THINK was where vapor vent was originally located. Now vented on backside of livewell housing

 

[SEMPERFI8387]

So is it still venting “outside” the boat or into an enclosed compartment? If it’s venting into a compartment I’d be concerned about vapor buildup and you know the potential outcome of that.

 

[Steelbreeze]

Outside but instead of underneath the deck it’s out of the back of the fishing station. I suspect the underneath vent was how water was getting in my gas tank. Going to run it and clamp a ballon around the now disconnected fitting and if it collects water I will assume mystery solved and the rerouted vent fix from dealer will have ended my issues

 

[Steelbreeze]

Here is new location of vent outlet

 

[Luvsthelake]

We’ll Good news, Bad news, Good news!
Good news- followed Lay Lake’s advice and confirmed the carbon canister, hoses and floor vent/screen are clear!
Bad news - the little black and white plastic piece in the first pic is stuck/ clogged. This is actually part of the fill neck and it goes to the carbon canister.
Good news - I sent the same message to Bennington and the are sending me the part under warrantee. They also advised that the dealer would install it but it might be easer for me to do it than get the boat over there. Meanwhile, ill be the one wit a “loose” gas cap! Thanks to everyone for your help and have a great Labor Day!

 

[Lay Lake]

Glad you found the problem and hope the part gets to you quickly.