[Casey B]

Okay well here's the update.
Before puttinaanything in the tanks I tried to wipe with my hands and it just rubbed off in little flakes that were slightly shiny. So I am going to say a petrolium based productNow it was only in the one side of the tank nothing around the drain which is on the filler side.
I took a clothe an wiped the residue off which except for some globs which look like drippings from a fat fryer it all came off. I then poured HOt Boiling water in and agitated it and the stuff seemd to melt and wash away with help. A wood paint stir stick helped.
Then after pouring that out and wiping dry with a clean clothe I decided to try a little gasoline and it did nothing to the stuff except turn it to a greasy gooy substance that smeared rather then wiped away...So much for the petrolium based substance.
It is curiously where the pick up tube goes and is the same colour as the element the strains the fuel at the pick up tube.
What is that made of...? Spongy red pourus material in a cylinder? Could be that is not compatible with todays fuels. Or the goo could have been an additive poured in that did not mix with the feul aka STP? something like that Or even sugar as it does look like varnish or burnt caramel! The pattern of the goo seemed to radiate outwards from the pick up tube in a radial pattern as the paicks show and then drip down.

Well there you are mystery not solved but problem gone.

The tank Bottom has some small patches of surface rust so I will look at getting it coated for new fuels.
Do radiator repair places do sealing of fuel tanks? Or I can google I guess!

Thanks fellows!