Gas Tank Fillup Problem ???

[OyBarBob]

My 04 21-Bay Boat with the 54 gallon tank will not allow me to fill same even though I pump the gas as slow as the station pumps will run; the gas overflows the fill hole with the overflow vent release not bleeding gas at all; hours later my vent will gush gas in one quick burst out of the vent hole and my efforts to add more gas result at most only 2 or 3 gallons while the console gauge will register just over ¾ full (gauges aren’t accurate, but I know approximately how much gas is needed from the run just made); my concern is twofold, first I love the boat and second on a recent run it ran out of gas (stop dead in the water) shortly after the gauge ‘suddenly’ registered empty; Sea-tow gave me 4gallons (gauge than register well over half full) and at the nearest marina where I ask them to fill it up, they were only able to add 37 gallons; after a 20mile run to the ramp, I was only able to add another 5 gallons before gas poured out the gas hole; from day one it’s always been tough to put gas in it, but with my going offshore more often it’s move from an annoyance to a problem of concern; something not right and I hate to get rid of a boat I love just because I’ve lost confidence in the fuel system that nobody can figure out why it can’t be fill up the after a days run.

[Tom Keels]

First off welcome!

You've got one of a couple of things wrong. You've most likely got either a kink or dip in your vent hose that is acting like a P trap under a sink preventing the gas fumes from escaping until the pressure builds up enough to push out past the fuel in the line.

Or when the boat was built they pinched the vent line when they put the hull cap on. Either way the problem is in the vent line.

What type of boat is it and could you take some pics of the vent and gas fill.

[Jumptrout51]

Tom is right on.

[tin can]

I would guess a sag in the vent line. Tom's on the money.

[OyBarBob]

Sea Boss 21 Bay Boat with 175hp Johnson; I got it at 'Jack's Boats & Trailers' in Perry Feb 05; the boat had 4 hours on it and all the warranties were in place; Hell of a boat.

My efforts to get a response from the Mfg in S.C. have been for naught so far and my ole Scandy-White is at Jacks for a new motor and he indicated we get one boat out of the shop and than we'll take a look at the other guy; I was 'hoping' for a Qwik fix. Thanx

[Dubble Trubble]

Some manufacturers will put a loop in the gas vent line. What happens then is that if the loop is too large, liquid gas will collect in the loop, then it will take a certain amount of pressure to push the liquid out of the loop so air can escape. That is where the gush of gas comes from. The heat buildup in the tank after an hour or so will cause enough pressure to push out the gas and then vent the air. This is also why you get gas spitting back, as the pressure is not enough to push the gas out of the vent, but enough to cause a spit back out of the filler cap.

I personally do not see why a loop is needed at all. If the vent is where water can enter it at all, then it is in the wrong place anyway. Some vents are inside the filler right below the gas cap(These tanks use a vented cap), and some vent to the outside somewhere high on the side of the hull.

Tom and Tin Can is also correct, a large sag in the vent line will give the same result by trapping liquid gas.

As for your gauge, I can bet it is totally unrelated to the vent problem, probably sticking (time to replace and/or recalibrate) or bad electrical connection somewhere.

Hooked

[Steve Stinson]

I had the exact same problem with a 2000 model Sea Pro (Same as hull as Sea Boss).

You have a crimp in the filler hose between the tank and the filler cap on the gunnel. Mine was slow to fill for the first 3 months that I owned the boat, then gas started showing up in the bilge.

I towed it back to Alafia Marine in Tampa, where I purchased the boat and they could not find the problem. I then contacted Sea Pro in S.C. and they asked me to take it to another Sea Pro dealer in Lake City. I towed it over there. We put it on a forklift and tilted in 9 ways from Sunday trying to get it to leak gas. No help.

Sea Pro sent a semi truck down and picked up my boat. Back at the factory, they figured out that the filler hose was too long and was crimped. That caused the slow fill, but worked okay until the part of the filler hose that was rubbing on the inside of the hull developed a hole in it. Then the gas would show up in the bilge, but it was only leaking when I added fuel to the tank.

Sea Pro originally thought I had a bad tank and offered to re-mount my motor and electronics on a new hull if they had to cut the floor. As it turned out, they had to cut an access hole in the inside liner in order to replace the hose. Then they installed a plastic cap to cover the hole (just like the one over your sending unit on your gas tank).

You are welcome to come look at my hull to see where they made the repair, and I would be happy to provide the phone number to Sea Pro if it helps. Jimmie Metz was the person I talked to there.

I will I.M. you my mobile number. Call if you have any questions.

- Steve Stinson

[OyBarBob]

Jack’s Boat & Trailers shortened the fuel line hose and the problem is now fixed; I can fill the tank completely and therefore know how much fuel I have when I leave the ramp which was a concern in the past.

[birddog]

good deal.

[Will_Fish_4_Food]

on the problem solved.

Sea Pro gets another look next time based on that story 4 sure!

[Flats Rascal]

Sea Pro sent a semi truck down and picked up my boat.

Wow.