[C320-list] Diesel Leak on Starboard tack

[Rick Sulewski]

Fuel tank leaks other than due to corrosion as the tank ages with corrosive debris collecting in the lower front port side corner of the tank where that stuff normally settles,  could also be due to the sender unit gasket leaking. Or, as I discovered, even the fitting screwed into the petcock ( fuel shut off valve located on top of the tank).  I found had a crack in that shut off valve fitting with some very old sealer dabbed around it (likely from with the tank was installed.....since I purchased the 320 new in Feb. 1995).  I was painted/smeared/lathered some NAPA thread sealer all around the sender unit gasket and over all of sender unit screws to curtail the sender fuel seepage since the new sender gasket was not sufficient to do the job. As I was ready to reinstall the storage shelf, I noticed moisture around the edge of the fuel hose connected to the shut off valve. When I grabbed the hose to twist it to see if was simply loose, the fitting separated with very little twisting pressure; my lucky day, really - fixing two problems during the same repair visit!

Regarding the aluminum fuel tank leakage due to aging and corrosive damage, I am going to buy a replacement tank soon, and plan to change out the old one this fall as a preventative measure to avoid a future fuel leakage problem. This year's sender unit seepage episode and subsequent clean-up processes convinced me I do not want to find several gallons of fuel in the area between the hull and the liner over the boating season or after a storage season. The marine service folks I checked with told me that they are now replacing a higher number of aluminum tanks for several makes of  boats built in the mid-80's thru early 90's. I learned that an aluminum tank replacement can occur anywhere from 10 to 20 some years depending on care of the fuel system with an expected tank life cycle of around 15 years. My hull was placed into service in spring of 95, so I going to replace the tank...I  routinely  draw a gallon or so of fuel from the front lower port corner of the tank every 4-5 years, but that is no assurance that I am getting the bad debris out because of the tank baffles and because without an inspection port in that area and must rely on access thru the sender port.

The  320 fuel tank replacement process would make an excellent technical notes article for the Mainsheet if anyone has some pictures of the tank replacement drill to share with 320 owners.

Rick
1995 My-Ria
320 Hull #277

-----Original Message-----
From: C320-list [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Doug Treff
Sent: Monday, August 04, 2014 11:55 AM
To: C320 List
Subject: [C320-list] Diesel Leak on Starboard tack

All,

I've been chasing a fuel leak for some time now. At first, I noticed that I would have diesel in my bilge after a fill-up. I suspected that the hoses and fittings on the top of the tank may be to blame, since I have no problems when I'm at 1/2 tank or less, or when the boat is level.

Friday I filled up and we motored 3 hours to our destination. We had a leak at first, but I cleaned up the mess and there were no more indications of a leak on the morning. The absorb pads in the bilge were clean in the morning. Saturday, we began sailing and after 30 minutes on a starboard tack, I had more diesel to clean up. When we arrived at our destination for the night, I changed the absorb pads. Two fresh sets of absorb pads later and the fuel leak seemed to have stopped. Sunday we motored about an hour and had no more problems.

I suspect that the fittings or hoses on the top of the tank may be leaking. Since these fittings appear to be towards the port side of the tank, they would be on the low side while on a starboard tack. Either the fill hose, vent hose, or the sender. Anyone else ever deal with this and if so, what did you do to fix it. I am really dreading the possibility that I may need to replace my tank, so I'm really hoping that its something a little less complicated.

I have a 1996 model, hull #350.

Thanks!

--
Doug Treff
doug at treff.us