Gas in bilge, very small amount 272 98 Sailfish

[steveg]

Just bought a 272 Sailfish. Filled up the reserve and put 75 gallons in the main tank. Ran the boat off shore 25 miles, fished all day. No Problems so Far. On the way back to the lift, put 120 gallons in the main tank. Tank said full. On way back. 3 miles. to the lift, smelled fuel. It was coming from the bilge. Opened all vents up and got her back on the lift. Pumped out a small amount and obviously noticed the gas sheen. Broke it up and then pumped the rest out into a 5 gallon bucket. Just a very small amount of gas on the top, verified it in a glass jar. Had to leave and went back 24 hours later, hoping the tank was not leaking. It was not leaking, again, miniscule amount of fuel in the bilge, this time I removed all the water in the bilge and rinsed it out. ANY IDEAS? My main theory is that the main line from the gas fill is either not tight or has a very minor leak. Of course, due to a poor design, I cannot get to the fill opening on the tank without removing the entire cover for the main tank. Any help will be appreciated.
Steve

 

[seasick]

There could be many reasons for the gas and you shouldn't spend a lot of time trying to see what conditions make the leak happen. Any gas or gas fumes in the bilge is not a good thing and is quite dangerous.
When you filled the tank, did you estimate the amount or did you fill until the gas nozzle clicked?
Since you added fuel to both the main and the reserve, you can't be sure which system is leaking either.
You could have a fill line leak, a sender flange leak, of a leak totally away from the tank fittings.
Unfortunately, I think you are going to have to open the tank up to see what is going on.
It is also possible that either tank has developed leaks in the tank itself. If near the top, the gas will leak more when full although these tanks can develop pin hole leaks anywhere, especially where mounting strips or straps are in contact.

 

[Parthery]

I agree with Seasick.

A 14 year tank (or two) is nearing the end of it's service life....and taking a chance can lead to things happening, none of which are good.

Pull the cover off and figure out where the fuel is coming from. A small amount probably means a fill hose....

 

[Tucker]

Steve,
A lot of us have these older boats. Please keep us current with developments.

 

[Grog]

It could be any number of things, sender, clamp, hose, tank,... either way you're going to have to pull the tanks & see. Even a small amount will produce enough vapors to blow the back of the boat apart.

 

[Tucker]

What a PIA. Can't fool around with this. What a way to spend the next couple weekends.

 

[steveg]

To all, thanks for the replies. The reserve tank was already full from a previous fill up so thankfully it was not involved. The main tank probably was filled up to probably around 130 out of 150 gallons. I agree with everyone, the main cover has to come off and then pump some fuel into the tank and see if there is any gas leaking. There was gas on top of the tank which leads me to believe it is the fill hose. Yes, it will be a total PIA. I do have a GW dealer 15 minutes away in OC if I have to use them. Thanks again. Steve

 

[CKJR]

pulling the tank cover off is not a big deal, I removed mine recently to check on & clean the tops of my tanks. Just have to cut the silicone caulking & remove the screws, the cover is a bit heavy but it will allow inspection. keep us posted

 

[Tucker]

Ck is right on. That hatch caulk should be replaced every so often anyway. Give you the opportunity to eyeball things and see how those leaky pie plates are causing your senders to corrode. Not a tough job to replace the hose. Razor knife and wire cutters will help alot. In this heat though, I may be inclined to pay someone to do it.

 

[cletus9000]

Yes, I had a fuel leak issue earlier this year, and it took removing the back hatch to find out what it was (not too difficult, but probably a 2-man job to lift off). Turned out that someone who had worked on the boat previously had not sealed the fuel sending unit correctly. Pretty easy fix, and once that hatch was off the source of the problem was very apparent. Hopefully it works out that easily for you as well.

 

[steveg]

Again, thanks for the responses. The plan is to bang it around the back bay in OC MD for 20 minutes monitoring if any fuel is leaking. I suspect it is coming from the sender. I had pulled it off to fix the actual sender unit and just hoping it was leaking from there. Should be easy enough to find out. I will keep you posted. Steve

 

[ROBERTH]

I would think you can pull up the pie plate and see if it is showing any signs of leakage around the fuel hose connections or the fuel sender seal without having to remove the floor plate?

 

[ahill]

When you changed the sender did any fuel spill on top of the tank.
When I changed mine I extracted it quickly and the fuel in the tube spilled on top of the tank eventually working into the bilge.
Squirt some dawn into the bilge to neutralize any remaining fuel.

 

[steveg]

To all, good news, had all the hatches (openings) and went up to plane, gas seeped out of the sender unit. Seal Bad. I will fix it on the 4th and go fishing. I had a 25' Trophy Pro for around 13 years and the tanks (original), etc were solid. I really did not suspect the main tank had a leak in it. Any way, cheap fix for a potentially dangerous situation or an expensive fix. Again, thanks to all. Steve

 

[Tucker]

Big mistake guys make when installing the sending units is to tighten the screws too much; the gasket will distort and not seal. Grease the screws and snug tight only. I have a new spare seal and gasket set that I would be happy to mail you. Shouldn't take long to get. I'm in Elkton, Md. I have 2 sets as spares and be happy to give you one. Send me your address.

 

[steveg]

Tucker, thanks for the offer and advice. I actually have a new gasket and screws and will torque it down gently vs too much. Steve

 

[steveg]

Again, thanks to all who replied. I found the cause of the leak. It was definitely related to the gasket. The 5 screws holding down the fuel sender unit looked like they were the same size, they were not. One screw was a bit longer that the others, 2 threads longer and in the position facing the stern, the screw was not flush, it was tight, but not flush, thus allowing the fuel to escape. A new gasket, repositioning of the screws solved the problem. Go figure. Steve