20601 Old State Road Haubstadt, Indiana 47639
The fuel system on Hercules built hit and miss engines is rather
simple, but a few comments are in order. Nowadays many original
engines have rusted or gummy fuel tanks. Starting off with a new
fuel tank is likely the best option rather than patching, using
sloshing material or using solvents to remove gum. Ready-made new
tanks up to the 7-8 HP size are available from several suppliers.
Be sure that the replacement tank has a vent on the top; otherwise,
gas will bubble out when filling the tank.
Tanks were held in the engine base with a combination of wires
and rods, although the design changed somewhat between the older
and new models. If the fuel spout is missing, replacements are
available on the used parts market, and new ones with the flip top
lid are available from some suppliers for the 1-2 HP size
For more trouble free operation, the fuel supply pipe should
have a fine mesh brass screen soldered into the end of the pipe to
keep out dirt particles that may be in the fuel tank.
Check valve sticking is becoming more of a problem. Apparently,
modern day gasoline tends to gum up more easily as it ages compared
to the regular leaded gasoline of several years ago. Drain the tank
To get good tight connections, it is best to use new brass
fittings and new tubing for the supply line to the fuel mixer.
The fuel adjustment valve should have a good clean smooth point.
If needed, a new valve can be made from ready bolt or the old one
can be put in a lathe and the point redressed. The valve seat
rarely requires attention other than to see that the hole to the
supply line is open.
The accompanying illustration shows some of the features