On Mon, 19 May 2008 18:22:15 GMT, Reno wrote:

Modern gas has so many additives that
if there is old gas in the tanks or cabs they may be gummed up and you have
to take them apart and clean the whole mess

On the contrary: modern gas has much less of a tendency toward gum
than a straight from the cracker and stills product.

They put additives in gas to, among other things slow the formation of
gum. They test for tendency to gum with a heated copper dish. I have
only one volumn of the ASTM standards. The one I have is on fuels and
I read it a while ago, I and I don't remember what all they said about
gum.

That said gum does exist. I have seen it in a garage sale lawn mower.
I have no idea how long it sat unused with perhaps years old gas in
it.

Fuel is among the most perishable of the things Army stocks. Ammo
lasts nearly forever, and food years longer than gasoline. They sell
an additive specifically to put in the fuel in your boat when you lay
it up for the winter. Never used it, never had any trouble in fifty
years.. Gum is a possibility but modern gas is really good in that
respect.

Casady