I think my fuel tank is shot

jwws9999

Cadet
Joined
Apr 24, 2011
Messages
10
I have a 96 larson cabrio with a 120 gallon tank, got the boat up on plane and gas started pouring out the hole in the bulkhead between the tank and the bilge. doesn't do it when the boat is at the dock, only when the engines are running and the harder the engines are running the more gas comes out. pretty scary stuff. any advice besides the obvious of replacing the tank
 

GA_Boater

Honorary Moderator Emeritus
Joined
May 24, 2011
Messages
49,038
Welcome aboard.

At risk of saying the obvious, yes, the tank probably needs to go. But take a look first, a hose may have broken or something simple hopefully.

Most importantly - Don't use the boat until it's fixed or we will hear about little pieces of you floating the water.
 

smokeonthewater

Fleet Admiral
Joined
Dec 3, 2009
Messages
9,838
Step 1 remove ANY source of ignition.
Step 2 remove all fuel.
Step 3 using ONLY hand tools and no power tools gain access to fuel tank and hoses

Determine cause of leak and replace whatever is damaged.
 

tpenfield

Moderator
Staff member
Joined
Jul 18, 2011
Messages
17,624
I have a 96 larson cabrio with a 120 gallon tank, got the boat up on plane and gas started pouring out the hole in the bulkhead between the tank and the bilge. doesn't do it when the boat is at the dock, only when the engines are running and the harder the engines are running the more gas comes out. pretty scary stuff. any advice besides the obvious of replacing the tank

It seems like we the responders are more scared than you are. Wondering how you made it back alive :noidea:

Could be just a fitting or the sender mount has come loose, but if not an obvious problem, I agree, off load the fuel and make no sparks. Post some updates as you are able.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,036
Fuel tanks can leak from fill, vent and fuel pickup fittings, as well as fuel gauge sender, in addition to holes in the tank. Normally they develop leaks in the tank itself near the bottom, where water and debris collects. Obviously you need to find the source of the leak. Since it leaks when the engine is running, I would inspect the antisiphon valve, fuel pickup line and fuel gauge sender first, followed by the vent and fill hose fittings.
 

jwws9999

Cadet
Joined
Apr 24, 2011
Messages
10
thanks alot guys, needless to say, this has been an extremely stressful situation. I have taken all those precautions, and yes, it was not a fun experience. I checked all the hoses and fittings. don't have anything coming from the sender.

Where is the antisiphon valve and what does it do. Like i said, it doesn't leak at the dock, just when the engines are sucking fuel, and the harder the suck, the more the fuel that leaks
 

jwws9999

Cadet
Joined
Apr 24, 2011
Messages
10
than that's not it. I'll call larson today and see what they have to say. hopefully they don't blow me off. the fuel tank manufacturer (skyline) doesn't make aluminum tanks anymore, so that will be interesting. they also had a recall on the 270 and 290 cabrios for fuel tanks but not the 310.
 

KnotConnected

Petty Officer 1st Class
Joined
Aug 15, 2012
Messages
221
Hey!

a) good luck with this issue!! Sounds like a total headache
b) Please don't tell me you're '96 is a Cab280..
b.5) If it is, could you keep us up to date with what the issue was, if they have any idea what caused it, and (most importantly) what the cost to fix was?

Thanks!

-A fellow concerned Larson owner (who really didn't need another thing to worry about with his boat)
 

tpenfield

Moderator
Staff member
Joined
Jul 18, 2011
Messages
17,624
So, it is a Larson Cabrio 310 (right?)

When you say the fuel spill is only when the engines are running at speed . . . is that because the boat is at cruising speeds and the the bow is tilted up? Or is it more of a result of the engines going at a higher RPM . . . so if you revved the engines at the dock would fuel spill then?

or is it only due to the motion of the boat?
 
Last edited:

jwws9999

Cadet
Joined
Apr 24, 2011
Messages
10
called Larson, they haven't heard of that problem. also, the boat was built by them for carver and they have no info including the bill of material for the boat, or drawings and instructions on how to get the tank removed.

i get no leak when parked and engines off, a small stream when revving the engines at the dock, bigger stream when idling down the river, huge stream when on plane.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,036
Gee, it sounds like a leak in the fuel pickup line somewhere. Likely just downstream of the antisiphon valve.
 

jwws9999

Cadet
Joined
Apr 24, 2011
Messages
10
I'll be pulling the floor off the aft cabin to see the rest of the tank, maybe there's a line I can't see, but it looks to me like all the lines and fitting go to the front of the tank where I can see them. I'll keep you guys posted. I hate it when people post questions and problems, and never tell anyone what the ultimate solution was
 

Maclin

Admiral
Joined
May 27, 2007
Messages
6,761
Did this just start happening and was ok before? Or is this boat new to you?
 

jwws9999

Cadet
Joined
Apr 24, 2011
Messages
10
just started happening, bilge was dry all winter with fuel in the tank. took it out the first time sunday
 

smokeonthewater

Fleet Admiral
Joined
Dec 3, 2009
Messages
9,838
There's no way it's the pickup line... That is under vacuum with the engines running... If running the engines (and not moving the boat) causes the leak then it HAS to be after the fuel pump...
 

jwws9999

Cadet
Joined
Apr 24, 2011
Messages
10
I found the issue, drained the tank of fuel, and filled the tank with water. Looks like the previous owner had a battery let go, and the acid ran across the floor into the side of the fuel tank. It created a pretty impressive hole, water was shooting out pretty hard when I filled the tank. getting that tank out is going to be anight mate, bit I do have access to the top of it. thinking of replacing it with one of those flexible fuel tanks. I could probably patch it from the inside, but not sure
 

tpenfield

Moderator
Staff member
Joined
Jul 18, 2011
Messages
17,624
with an 'impressive' hole, I would be doing a new tank and not relying on a patch kit. Keep in mind that if the fuel tank is foamed in it may be providing some structural rigidity to the boat which would be lost on a different kind of installation.
 
Top