Generac Power Systems GTV-990 Manual page 23

FUEL PUMP
The fuel pump supplied with the engines is a pulse pump.
It uses crankcase vacuum pulses drawn from the valve cover
of cylinder #2 to pump the fuel. It is capable of priming at
12" (30.5 cm) max lift. The pump has a max outlet pressure
of 1.5 psi.
If a fuel pump other than the one described above is used,
the fuel line pressure at the carburetor inlet must not exceed
3 psi. Pressures in excess of 3 psi may cause an over rich car-
buretor mixture that would lead to engine damage.
TO
CARBURETOR
INLET
FUEL FROM
TANK
PULSE LINE
Figure 3-6. Fuel Pump
3-3
SECTION 3: CARBURETION