Fuel Tank Help

#1 02-01-2010, 01:07 PM

I need some advice. After refueling the last trip, I had a really heavy gasoline odor from the bilge - actually coming out of the anchor locker on the bow. I traced it to this aft access port. Fuel was "oozing" from under the rubber gasket you see in the pictures. This is the fuel pickup port - the fuel fill and overflow are on the other end of the tank and they look fine. I pushed down and fuel came out under the gasket. So - I removed it. As you can see, the screws mounting the fuel pickup are three different sizes. The fuel has taken the paint off the tank.

Here is where I need advice: I rethread those holes and replace all the bolts - no problem. Question is do I need some type of gasket sealant, or will the rubber gasket suffice with good bolts? One bolt was completely stripped and I believe the gas was coming from that side of the gasket. Any thoughts?

Rainmaker · #2 02-01-2010, 01:21 PM

Be very careful what you put on the bolds or around the opening. I had a buddy who purchased a boat and had all sorts of fuel issues. When we drained the tank we found a few little dots of RTV (or something like it) that were from the threads of the screws. When we dropped these in fuel it was amazing how they grew. It looked like they would get sucked up into the fuel line and plug it up. It took some significant effort to get the tank cleaned and operating as it should.

I just replaced my sending unit and did not put anything on it. The rubber gasket was good enough.

Bushwacker · #3 02-01-2010, 02:20 PM

Gas odor in the cabin of my Seafari is absolutely unacceptable when I sleep aboard, so I'm pretty fanatical about sealing the fuel tank! The old Permatex Non-hardening No. 2A Form-A-Gasket is a little messy but it works well; put some on both sides of gasket and on screw threads. (wear vinyl gloves if you don't want it on your fingers for a couple of weeks!) Don't use any type of RTV or anything with silicone in it, as it's not compatible with gasoline.

Fr. Frank · #4 02-01-2010, 03:34 PM

Quote:

Don't use any type of RTV or anything with silicone in it, as it's not compatible with gasoline.

Absolutely right! Permatex 2A is the way to go. However, I would use Permatex #12020, Instant Gas Tank Repair between the gasket and the tank if you have any pitting under the gasket.

#5 02-01-2010, 07:48 PM

Quote:

Don't use any type of RTV or anything with silicone in it, as it's not compatible with gasoline.

Absolutely right! Permatex 2A is the way to go. However, I would use Permatex #12020, Instant Gas Tank Repair between the gasket and the tank if you have any pitting under the gasket.

I went with the Permatex 2A. The pictures look like pitting, but it is just crud. I cleaned it off and it is now back together. I have the tongue of the trailer down so the fuel is away from the port. I'm letting it cure overnight and I'll be checking to see that it does not leak in the morning. Thanks guys!!

3rdday · #6 02-03-2010, 11:13 PM

Silicone will swell with oil and fuel, unless it is a Flourosilicone, whick you wont find. it is sold as gum stock to injection molders, use as o ring material and fuel hose liner in aerospace and automotive.
Also a big mis understanding- silicone is a terrible adhesive unless used on glass. for this application you need an adhesive and sealant.Good choice on the permatex.
Also never use silicone to seal holes- use a polyurethane such as 3m 5200 UV or Sika, Bostic etc

Wags23 · #7 02-04-2010, 01:23 PM

The builder of my tank in mass used silicone on the sending unit so he could get apressure reading.It turned in to a nightmare clogged my fuel system. Ended up having to replace fuel reg and fuel pump. I did all the labor and trouble shooting still waiting to be reimbursed for just my parts.

Tiny · #8 02-06-2010, 11:46 PM

Never seen a bolt on pickup, just welded on ones. Is that an OEM tank? I've pulled two OEM tanks both had welded on pickups...no big deal just an observation. My tanks were from a 74, 20 scepter, and a 70, 20 safari.

Fr. Frank · #9 02-07-2010, 07:29 PM

Quote:

Never seen a bolt on pickup, just welded on ones. Is that an OEM tank? I've pulled two OEM tanks both had welded on pickups...no big deal just an observation. My tanks were from a 74, 20 scepter, and a 70, 20 safari.

My original tank on my '72 Seafari had two "bolt-on" ports in the tank top. One was for the fuel pick-up just like above, and one for the sending unit. They were about 10 inches apart. My new tank has a welded pick-up, but retains the bolt-on sending unit.