Weifang 495 - Page 79

8
9 ./
-
6
.------
Fig. 1·8 Feed Pump
1---- Hand pump; 2-- Check valve; 3- Pump housing; 4-- Inlet banjo connec-
tion bolt; 5-Push rod; 6-Piston; 7-.Piston spring; 8-0utlet banjo connection
bolt; 9-Check valve.
. The maill function of the feed pump is to keep the low pres-
sure fuel passage full of fuel with certain pressure.
The feed pump is of automatic' pressure regulated ty'pe to en-
sure the fuel pressure stead}Y, When the fuelpressu!ewithin the
low pressure fuel passage exceeds 49KPa, the fuel pressure will
compress the resilieIlt ,spring through the piston to make the pis-
ton apart from the push rod gradually and as a result, the fuel de-
livery will be reduced or stopped.
The hand pump is used to make the fuel delivery system ex-
pelling the trapped air out and being full of fuel before the engine
starting. When it isn't in use, ~he hand' pump piston should be de-
pressed down and the knob should be tightened ,so that the oil pas-
44