Fueling Up in HOT Weather - Venting Issue - Side Fill - Above 105 degrees...ish.

[LaurencetheAdventurer]

I know there are various posts about the venting issues when filling our Benny's gas tank: I had the issue twice last season and again this weekend - during the winter dealer could not find anything on this issue. This is with a Side Fill tank. Ideally this might help others with diagnostics in hot weather:

On day one we arrived late afternoon, it was 113 degrees out, the boat had been sitting in the water for a couple of weeks with 110 degree plus heat. I did not have a chance to fill it up at the prior visit (I try to keep my tank full). I pulled up to my normal dockside station, and could only get 12 gallons on top of the 15 that was already in the 56 gallon tank - the gas was burping (high flow) / draining (low flow) out the fill hole, no matter how slow I filled. So I went out and enjoyed the day.

The next morning I hit the gas station early (it was just under 100 degrees) and no issue - filled it up.

Next day I filled at the end of day (7pm), temperature had dropped from 117 down to about 104 (small monsoon had rolled in). No issue again filling up.

SO - I theorize MY venting / filling issue is related to temperatures in excess of 105 degrees, particularly when the boat has sat and the tank is hot (and probably hot coming out of the pump). Not sure WHY, but seems if the gas is venting excess fumes (from being so hot) the new EPA system is somehow preventing / blocking / slowing my filling ups.

Possibly this expands / offers additional options to into the excellent posts by gnc1017 Sept 4 2018 and Sparetime Jan 10 2022 about Fuel Venting / Fuel Fill problems - plus another half dozen posts. I will continue to monitor and test.

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Picture for Fun Factor....

 

[BigKahuna]

Never had any issues filling up either of our pontoon boats. One had a side fill and the other a direct fill in front of the outboard. But then again it's not 113 to 117 degrees either! I remember flying into Vegas when I was younger. The pilot said it's currently 112 degrees! Down from 114 yesterday. But folks it's a dry heat! Whatever!

 

[Bill N]

I remember flying into Vegas when I was younger. The pilot said it's currently 112 degrees! Down from 114 yesterday. But folks it's a dry heat! Whatever!

That was my thoughts on Phoenix as well. Stepping off the plane I said to my wife..."Dry heat my a__, let's just stay on the plane and go back home!"

 

[BigKahuna]

That was my thoughts on Phoenix as well. Stepping off the plane I said to my wife..."Dry heat my a__, let's just stay on the plane and go back home!"

Ha! I hear ya!

 

[jcr159]

I know there are various posts about the venting issues when filling our Benny's gas tank: I had the issue twice last season and again this weekend - during the winter dealer could not find anything on this issue. This is with a Side Fill tank. Ideally this might help others with diagnostics in hot weather:

On day one we arrived late afternoon, it was 113 degrees out, the boat had been sitting in the water for a couple of weeks with 110 degree plus heat. I did not have a chance to fill it up at the prior visit (I try to keep my tank full). I pulled up to my normal dockside station, and could only get 12 gallons on top of the 15 that was already in the 56 gallon tank - the gas was burping (high flow) / draining (low flow) out the fill hole, no matter how slow I filled. So I went out and enjoyed the day.

The next morning I hit the gas station early (it was just under 100 degrees) and no issue - filled it up.

Next day I filled at the end of day (7pm), temperature had dropped from 117 down to about 104 (small monsoon had rolled in). No issue again filling up.

SO - I theorize MY venting / filling issue is related to temperatures in excess of 105 degrees, particularly when the boat has sat and the tank is hot (and probably hot coming out of the pump). Not sure WHY, but seems if the gas is venting excess fumes (from being so hot) the new EPA system is somehow preventing / blocking / slowing my filling ups.

Possibly this expands / offers additional options to into the excellent posts by gnc1017 Sept 4 2018 and Sparetime Jan 10 2022 about Fuel Venting / Fuel Fill problems - plus another half dozen posts. I will continue to monitor and test.

​

Picture for Fun Factor....

any additional insights? I'm chasing what looks like a vapor locking issue when under power, albeit not temp related... but can't help but notice that i've had the tank at half full or less most of the season, and recently filled to 3/4, and i'm getting fuel flow issues... primer bulb is completely collapsed. boat is new this season, so not a rot issue... feels like something on the venting system is blocked or not working properly...

 

[LaurencetheAdventurer]

any additional insights? I'm chasing what looks like a vapor locking issue when under power, albeit not temp related... but can't help but notice that i've had the tank at half full or less most of the season, and recently filled to 3/4, and i'm getting fuel flow issues... primer bulb is completely collapsed. boat is new this season, so not a rot issue... feels like something on the venting system is blocked or not working properly...

Fuel Flow Issues - I think a completely different topic, but: If some type of vapor lock, then removing the gas cap would fix that, but doubtful this is the issue. My 2021 had issues caused by a loose connection with the gas tank that was sucking up air. Otherwise, it may be just a bad fuel pump or clogged filter (based on other posts I have read). Be sure to search this forum and Facebook, Primer Bulb and Fuel Flow and/or the actual issues you are having would be good search terms.

 

[jcr159]

Fuel Flow Issues - I think a completely different topic, but: If some type of vapor lock, then removing the gas cap would fix that, but doubtful this is the issue. My 2021 had issues caused by a loose connection with the gas tank that was sucking up air. Otherwise, it may be just a bad fuel pump or clogged filter (based on other posts I have read). Be sure to search this forum and Facebook, Primer Bulb and Fuel Flow and/or the actual issues you are having would be good search terms.

For others benefit in the future....

If you see the primer bulb sucking in/empty/vacuumed, with engine cutting in/out at higher throttle settings, but fine at lower throttle, it's likely a kinked fuel line. If you have shielding under the deck, it's a royal PITA to find/deal with. Luckily, my dealer came out and fixed it under warranty. said there was just way too much line left in from the tank to the motor after rigging, and it jus worked its way into a kinked position over the first 45 hours..

 

[LaurencetheAdventurer]

So I continue this season with the same issue - in the spring I have no issues filling the Benny in under 100 degree temps. This weekend it was 110+, as I filled the gas tank (from the same dock pump as always) it would backup and flow out the fill neck. Worked ok if I slowed the pump down a lot, but I had 45 gallons to go. I tried placing the fill nozzle upside down, that worked a LOT better, especially if I fidgeted with the nozzle between pulling up and pushing down while upside down. I don't recall which worked better, but one of those combo's allowed me to fill at 3/4 speed (vs the 100% pump speed I am normally able to do). Just an FYI.....

 

[DVW]

I cannot address why your problems are temperature related but I know the new side fill systems are finicky and probably sensitive to more than one factor. The newer complex fuel fill systems are suppose to kick the fuel fill nozzle off before the fuel level reach’s the side receptacle. If you look into the filler hole you can see a pressure pickup inline with the flow coming out of the fill nozzle. The pressure pickup sends flow to some sort of configuration?? at the top of the tank. When the resistance to flow in this line exceeds a certain level (for a multitude of reasons) flow backs up to a spot that is inline with a small side port at the end of the common gas filler nozzle. When this small side port is exposed to gas it shuts off the nozzle in your hand. Rotating the fill nozzle in your hand can stop this chain of events but not without other consequences. When I replaced the tank in my boat I ran into these issues. I cannot recommend my solution but what I did was reduce the ability of the pressure pickup to pickup pressure. To do this I rotated the pressure pickup that I am holding in my hand in the photo within the attached link. That side fill modification work well but since then my boat has evolved with two direct fill tanks. That is more elegant but a bit aggressive.
Enviro Fill Bypass | Club Bennington

 

[LaurencetheAdventurer]

I cannot address why your problems are temperature related but I know the new side fill systems are finicky and probably sensitive to more than one factor. The newer complex fuel fill systems are suppose to kick the fuel fill nozzle off before the fuel level reach’s the side receptacle. If you look into the filler hole you can see a pressure pickup inline with the flow coming out of the fill nozzle. The pressure pickup sends flow to some sort of configuration?? at the top of the tank. When the resistance to flow in this line exceeds a certain level (for a multitude of reasons) flow backs up to a spot that is inline with a small side port at the end of the common gas filler nozzle. When this small side port is exposed to gas it shuts off the nozzle in your hand. Rotating the fill nozzle in your hand can stop this chain of events but not without other consequences. When I replaced the tank in my boat I ran into these issues. I cannot recommend my solution but what I did was reduce the ability of the pressure pickup to pickup pressure. To do this I rotated the pressure pickup that I am holding in my hand in the photo within the attached link. That side fill modification work well but since then my boat has evolved with two direct fill tanks. That is more elegant but a bit aggressive.
Enviro Fill Bypass | Club Bennington

Great info, I had saved your previous advice and keep it on file - thank you. Note - our station requires you to manually hold the filler nozzle - no locking device. The filler nozzle in my hand does not shut off in either direction, at least not immediately (I stop at the slightest trickle out of the neck). Rotating the hand nozzle results in the gas NOT backing up and leaking out the fill throat - in the normal position, the gas starts leaking out / gurgling quickly at anything higher than 1/4 speed. Rotating the hand nozzle I can go to 3/4 speed. When it is under 100 degrees out, I can fill normally at 100% flow. I have not been able to come up with any answer to why this is, but FYI for all those with issues when filling - try rotating the filer nozzle 180 degrees.