ST 100 with leaking petrol tank.

[rayray]

Greetings from New Zealand .
Well forty years ago , a Homelite ST100 made its way over the sea, and two owners later, it is now in my possession. 
I have a bit of a linetrimmer/ reel mower fetish, and this one tickles my fancy.
I have got it running beautifully, but there is a leak at the bottom of the tube tank, and it is stopping me using it.
Does anyone know of a fix?
I am not sure if I can safely remove the bottom plastic insert from the aluminium tube handle. Is that possible.
Otherwise I was thinking of injecting dome epoxy sealant up through the fuel outlet at the bottom.
Any advice would be much appreciated. Thank you,  Ray

[blythkd]

The O-ring that seals the plastic insert to the aluminum tank tube is probably cracked and leaking. Remove the tank/tube from the engine housing, pull the plastic piece out of the tank and replace the O-ring. Next before you re-insert the part back into the tube, take a small round file like a chainsaw file, and remove any burrs from the inside of the aluminum tube around the bolt hole (bolt that secures tank to engine housing). The serrated shank bolt usually causes burrs in the hole through the tube that will cut your new O-ring if you don't remove them before reinstalling the plastic insert.