Time to check my fuel system for leaks. I had tested the tanks individually for leaks with gasoline before and found a few leaks around the inserts, which I was able to fix by reheating the inserts. Filled 23 gallons of diesel fuel into the tanks, 5 gallons at a time and checked for leaks. After a while the lower left tank started aslow leak around the lower left insert. After aday of sitting anothe very small leaks developped around the three bottom inserts of the left bottom tank. The leaks were minor and were not visible with gasoline, bacause gasoline would evaporate quicker than gasoline would leak out to create a puddle.
Sure don't feel like taking out the left lower tank again to fix these leaks. For now, I used a neoprene washer to fix the leak temoraryly. Will need to come up with a permanent solution eventually.
There are currently no replacement tanks available from Heliccle ventures.
