It may be a good idea to make sure it's really leaking where you suspect. Do you have a pressure source like a blood pressure bulb, or low pressure (5-10 lbs) air compressor and a pressure gauge? After emptying the gas and bar oil, connect a pressure line where the fuel line comes out of the tank and tee it with the gauge. I'd use some plastic wrap and screw down the cap. The plastic wrap will keep from blowing out the duck bill on the cap and make sure its sealing up there. Apply pressure and pressurize the fuel tank. Notice the gauge and see if its leaking down. If its bad, you can probably hear it. If its slow, you might put a little kerosene in the bar oil tank to see where the bubbles are leaking through.
This sounds like a lot of trouble, but I'd want to know for sure where the leak is, and how bad it is. If its leaking at the seam where the gasket is where the two tanks touch, I can think of a couple choices. Hardest way would be to separate the tank, smooth the surfaces, and put in a new gasket. Those philips head screws can be a pain to remove. May need to heat, and use an impact tool to get 'em loose. I've never used the stuff, but guess the easiest way would be to get some gas tank sealant and apply inside the fuel tank.
Dan
