gulfstream 232 fuel tank issue

[swlandino]

I noticed a fuel smell when I filled the main tank of my 232. Did an inspection. No fuel or liquid in the bilge. Never have had that.

The fuel intake line was badly cracked near the fill end allowing gas vapor to escape. Removed both deck covers for the aux and main tanks and examined both tanks in place. All inputs and outputs were vapor and liquid free. I replaced the fuel intake line, as it was the main suspect for source of the fuel smell. Filled to half the tank, no fuel smell. Thought I was done. A month passed during which time I used the aux tank. Yesterday I filled the main to full, about 80 to 90 gallons. A strong fuel smell in the cabin and cockpit resulted! Checked the new line connections and they were secure and not leaking. Checked the bilge in the stern and observed fuel. Carefully removed 4 gallons of fuel by hand and disposed to marina staff!

What was causing the fuel leak? Certainly NOT the main fuel intake line, and not the aux tank. No fuel or smell with the aux tank filled.

I survived venting all vents while using the remaining main tank fuel underway down to maybe 10 gallons. That is where I am now. My first hypothesis now is my tank is leaking, but the leak source is not visible when the tanks are exposed. I am in the field on a fishing trip in Ensenada. My conclusion is to refrain from using the main. It likely needs replacement. My 232 is a 1999 hull powered by a 2021 4 stroke Yamaha 300. I feel I dodged a bullet running the boat with what appears to be a leaky main.

I see nothing else to check in the field. There is no smell or liquid in the bilge running the aux tank. I intend to keep fishing using the aux tank exclusively. Comments please! Thanks much.

 

[seasick]

If I were a betting person, I would bet on bad fill or vent hoses first and leaky sender second.
You also didn't make it clear (at least to me) if you smelled and saw gas after filling BOTH thanks or just the main. Do your tanks have combo fill/vent fittings or separate vents?
When yo initially replaced the fuel fill hose, you should have replaced the vent hose also.
The metal tanks typically start leaking on the bottoms first and that doesn't seem to be your case. Leaky sender is more likely. Four gallons in the bilge is not a small leak and may be sender related since it will leak when the tank is mostly full to really full. Once the level gets lower than the top of the tank, the leaking will for the most part stop at rest. Getting on plane will force gas backwards and can leak at a bad sender seal too.

 

[swlandino]

If I were a betting person, I would bet on bad fill or vent hoses first and leaky sender second.
You also didn't make it clear (at least to me) if you smelled and saw gas after filling BOTH thanks or just the main. Do your tanks have combo fill/vent fittings or separate vents?
When yo initially replaced the fuel fill hose, you should have replaced the vent hose also.
The metal tanks typically start leaking on the bottoms first and that doesn't seem to be your case. Leaky sender is more likely. Four gallons in the bilge is not a small leak and may be sender related since it will leak when the tank is mostly full to really full. Once the level gets lower than the top of the tank, the leaking will for the most part stop at rest. Getting on plane will force gas backwards and can leak at a bad sender seal too.

Thanks for your comment. Only had fuel smell associated with filling the main. I have two deck access ports over the main and I checked the sender and all other hoses (including the overflow) and they were not damaged or leaking. I will check them again though. Nor was there any fuel on or around the top of the tank. I may have a side leak on the main. Unless I can determine another route I intend to keep away from using the main this trip and remove the tank when I get home.

You are right about the leak though. Must not be small. That said, after I fueled the main I fished hard that day and discovered the fuel at the end of the day. It was a bit rough and the full main had opportunity to leak throughout the day due to the jostling of the boat, even from a top or side of the tank leak.

I do appreciate your comments however and will recheck the sending seal again.

 

[PaulinSeattle]

Hi - I recently purchased a 2004 Gulfstream and am having exactly the same issue you described. After reading your post, I don't see whether or not you ever completely diagnosed the issue down to the sender unit, or vent hose, or fill hose. Did you ever discover source? I've only had boat for about 2 months now and haven't pulled the deck to check but before I do I thought I'd check and see if you ever found your leak? Thanks.

 

[OceanSun]

Paul - I'm also in the Seattle area and bought a 2008 Gulfstream this summer. First fill up smelled strong fuel smell but without any fuel in bilge or fuel tank compartment. It ended up being a badly cracked fuel fill hose which I replaced along with the vent hose routed alongside it. Fixed the problem and not a hint of fuel smell since. Was leaking while filling and seeping down the outside of the filler hose until evaporated. Was afraid I had a leaky tank but relieved it was just the fill hose. Hose was badly disintegrated from ethanol fuel.