Hercules Engine News

Including Economy, Arco, Jaeger & Thermoil


| September/October 1995



Fuel system on Hercules engine

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 engines.

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 between seasons.

To get good tight connections, it is best to use new brass fittings and new tubing for the supply line to the fuel mixer.