Cleaning out fuel tank

[mitiempo]

Last year I replaced a 32 year old steel tank that did not leak but was rusty on top from a leak around the deck fill - what idiot would put the fill in the middle of the cockpit well anyway? I replaced it with a stainless tank I had custom made to fit. And relocated the fill to the side deck with all new hoses.
Amazingly the old tank was not that bad inside but it's days were numbered.

[MedSailor]

I don't know why you'd want to remove it. I bought a 5" diameter high carbon hole saw and cut some inspection ports in mine. There were fistfulls of gunk. Polished it out with some elbow length chemical gloves and a toilet brush. If I had to do it over again I would buy hole saws that are the same size as pre-made inspection ports instead of fabricating my own from pieces of plastic HDPE and drilling and tapping new holes.

MedSailor

[BluemanSailor]

I'm getting water in my fuel tank, and seeing that the tank is in my bilge I'm assuming that the inspection ports (there are 2) might need resealing. What did you use to seal the ports against the diesel?
thanks

[MikeinLA]

I had the same fears as you and so I recently had my tank cleaned. We have a fellow in my marina who's been doing it since 1976. He pumped out the fuel, cut 2 BIGA$$ inspection plates on the top on either side of the baffle and then hand-scrubbed the tank to a sparkling finish. I also had him put in a small screw-in plug so I can check the fuel level with a dipstick. Mine was all done in place, but the access to my fuel tank is absolutely superb. It's all going to depend on your tank location I think.

Mike

[pdqaltair]

Originally Posted by BluemanSailor

I'm getting water in my fuel tank, and seeing that the tank is in my bilge I'm assuming that the inspection ports (there are 2) might need resealing. What did you use to seal the ports against the diesel?
thanks

And don't forget a new o-ring on the fill. Far more common.

I think you'll find factory is generally silicone, if not a nitrile rubber gasket.

[BluemanSailor]

Thanks- that's the first thing I did, replace the o ring on both the deck fill and the 2 inspection ports. Next weekend when I go to the boat I'll rebed them. After much research it seems that the recommended sealant would be RTV Silicon Sealant. Hope I can find it.

[bwindrope]

Since I did not recall the original post saying anything about leaking, and only about gunk, I agree with MedSailor that there are far cheaper and easier options to replacing the tank. I replaced the tank on my old Ericson 28 and so know of what I speak.

Another idea in addition to the cleaning ports mentioned above, is to purchase some B99 biodiesel and run that through. Make sure you have a good Racor primary filter (which you should anyway) and prepare to change it out a few times in the beginning. Also, make sure your diesel runs on the hot side, if it is fresh water cooled. A common problem is to have a thermostat that has her running at 160 or so, when the combustion temperature of diesel, especially biodiesel is higher and benefits from higher operating temperatures. I replaced the 160 stock thermostat on my Gulf with a 185 and greatly reduced the soot on the transom and did wonders for my engine.

Anyway, I ran biodiesel a while, replace a few filters, did a self polishing of opening my tank and agitating it while running the fuel pump through the filter and back to the tank, and now my tank and fuel system is so damn clean I replace my filters every year just for the formality of doing it. They are pristine after a long hard season.