fuel smell.. uh oh

[sweet16fan]

Hi guys... well my first Donzi and its a swweeeet16... cept for that fuel smell in the bilge. its strongest under the floor right behind the tank. I know.. ugh. anyway .. anyone have any ideas before I take up the sawzall to remove the tank? any secrets I should know about ? its a 1990 sweet16 with 4.3 OMC and looks like fibreglas tank thru the round hatch.

[Ranman]

You'll get better replys from some of the veterans here, but I wouldn't sawzall anything. Most likely, If you don't have access to the problem or need to replace the tank, the most correct way to fix will be to seperate the hull and deck. Lots of guys here have done it and they insist it is not that difficult.

[sweet16fan]

I'll unplug the saw till I get lots more ino.. I had this brilliant scheme that I could make the tank easy to get to for next time by making a large access hole in the deck that the tank would angle out of.. it does not look too big. maybe I will get real lucky and find a leak I can get to .. its only fumes, no liquid i can see. But thanks for the advice. will check out the local group for events., am in Stuart. need to keep my distance til I get this project done.

[Formula Jr]

Sweet 16, it would be extremely rare for you to have a tank failure in so recent a model. So pack away the sawsaw, till you have double checked ALL the fittings to the tank just as Poodle suggested. You might even want to pressure test the system and look for leaks. You do this by draining the tank, and plug the fuel line to the engine. Make sure your gas cap has an air tight gasket on it. Now drop some dry ice into the tank till it has filled the tank and is out flowing from the fill. Wait for the dry ice to completely sublimate - till it stops flowing out of the fill hole. VERY IMPORTANT to wait till the dry ice has completely turned to CO2 gas. Its heavier than air so it will stay in the tank, but you do not want the CO2 pressurizing the tank. Tightly cap the fill and pump about 7-10 psi into the tank via the vent hose with a compressed air tank - be sure the compressor is off so it will not run the compressor motor and cause a spark.
Using soapy water, or air bubble solution, splash it all around your fittings and look for bubbles. Your most likely area of concern is the sender ring given your description of where the smell is coming from. Good luck.

PS. Do not wear wool over cotton clothing (creates static electricity) and take the battery out of the boat before doing this. And do not wax, polish or buff anything on the boat prior to doing this. Do not tow the boat anywhere just prior to doing this. Have a LARGE GAS FIRE RATED fire extingusher with in arms length or at the ready by a friend at all times.

PPS. Only do this in a well ventilated area - ... and I'll probably think of more warnings in about five minutes. :)

[Gearhead99]

sweet16fan, be VERY careful. Your comment about the fuel smell is a little off. You said, "It's only fumes, not gas". Whoa, remember liquid gas doesn't burn, only the fumes burn. The fumes are what's dangerous.

Please be careful. Don't want to read about you in the paper or see you on the 6:00 news.

[MOP]

All excellent stuff already said, these poly tanks are pretty tough. Not to say they don't fail, in the 16 they are fairly tightly fitted between the stringers and do not flex which seems to be the killer. I have changed out alot of water and pooper tanks that were on platforms with no side support. The only extra I think should be mentioned is that when you tighten any thing in poly you must rely on good sealants as nothing is tightened much past hand tight. It strips like butter!