Since the bottom of the tank is below the carburetor, it is pressurized off the back of the low speed center bearing rotary valve. They can be set up to run on the 6 gallon double line pressure tank. Carburetor/rotary valve set up similar to the Evinrude Lightfour and Zephyr. Same bore and stroke as the FD model. I often wondered how they would fit on the FD driveshaft/exhaust housing.
. . . . . . 😉
