Cub Cadet 8454 Service Manual page 39

a . Pump Element
The pump element (1) consists of a plunger (3) and
cylinder (2), their sliding surfaces are precision ma-
chined to maintain fuel tightness. The plunger (3) fits
in the control sleeve (5) at the driving surface (7). The
sleeve is engaged with the control rack, which rotate
the plunger in the cylinder to control the amount of fuel
delivery.
b. Operation of Pump Element
(A) Before delivery
As the taper lowers, the plunger (2) lowers and fuel is
drawn into the delivery chamber (1) through the feed
hole (4) from the fuel chamber (5).
(B) Beginning of delivery
When the plunger is pushed up by the cam and the
head of the plunger closes the feed hole (4), the pres-
sure in the delivery chamber (1) rises to push the deliv-
ery valve (3) open.
(C) Delivery
While the plunger (2) is rising, delivery of fuel continues.
(D) End of delivery
When the plunger rises further and the control groove
(6) on its periphery meets the feed hole, the fuel re-
turns to the fuel chamber (5) from the delivery chamber
(1) through the control groove (6) and the feed hole (4).
D569-W02 May-2003
K&T Saw Shop 606-678-9623 or 606-561-4983
www.mymowerparts.com
(1) Pump Element
(2) Cylinder
(3) Plunger
(4) Feed Hole
(1) Delivery Chamber
(2) Plunger
(3) Delivery Valve
ENGINE
569W231A
(5) Control Sleeve
(6) Control Groove
(7) Driving Surface
569W232A
(4) Feed Hole
(5) Fuel Chamber
(6) Control Groove
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