Fuel Pump Service Instructions - Wisconsin VH4D Repair Manual

FUEL PUMP SERVICE INSTRUCTIONS
WISCONSIN FUEL PUMPS, No. LP-38E, LP-38H and LP-38F (Cold Weather: -65°F)
For all 4 cylinder engine models
The fuel pump, like all other parts of the engine, is sub-
ject to wear and you will find that any time after 500 hours
of use, its efficiency will gradually decrease. This is in-
dicated by the engines faltering at high speeds or when
heavy loads are suddenly applied. The pump can easily be
restored to its normal efficiency by the installation of a
repair kit. Wisconsin LQ-46 (for LP-38E), LQ-47 (for
LP-38H) or LQ-46A (LP-38F, cold weather, -- 650).
1. Disconnect fuel lines from pump and remove fuel strain-
er if mounted to pump. Remove fuel pump from adapter
housing by taking out the two mounting screws.
2. File a groove across a point at the union of castings
(15 and 16). This is a positive location of the fuel
INLET and OUTLET positions when reassembling. Re-
move six head to flange screws (3) and remove fuel
head. Take off screw (2), remove cover (7) and discard
cover gasket (4).
3. Turn fuel head (16) over and remove both valve assem-
blies (5), and gaskets (6). Note position of valves.
4. Clean head thoroughly with kerosene or diesel fuel and
a fine brush.
5. Place fuel head (16) with diaphragm surface up. As-
semble new valve gaskets (6) and mount valve assem-
blies (5) in positions shown on illustration. Press
valves in evenly without distortion, and stake in place.
6. Mount new cover gasket (4), cover (7) and washer
Securely tighten in place with cover screw (2).
7. Set fuel head assembly aside and proceed to rebuild
lower diaphragm section.
8. Insert the end of a small screw driver into the coils o£
rocker arm spring (12) and remove.
9. Hold mounting bracket (15) in the left hand, with the
rocker arm toward your body and the thumb nail on the
end of link (10). With the heel of right hand on dia-
phragm (1), compress the diaphragm spring (11), and
the same time pull toward your body. Unhook link (10)
from end of diaphragm and remove.
10. Remove rocker
arm pin (13). Note that pin is larger
one end. Drive pin out by means of a punch from
small end.
11. Clean mounting bracket (15) with kerosene or diesel
fuel.
12. Assemble new link (10), bushing (9) and pin (13)
bracket (15) along with rocker arm (14). Stake rocker
arm pin (10) in bracket to keep it in place.
13. Place new diaphragm spring (11) into
bracket (15).
peat in reverse order paragraph 9, using a new dia-
phragm (1). Assemble new rocker arm spring (12).
14. Mount this assembly to adapter on engine using new
flange gasket (17).
15. Crank the engine over to a position where the diaphragm
(1) is laying flat on the mounting bracket (15). Place
the fuel head assembly back in position so the locating
grooves of Step 2 are in Fine, and start the six head
screws approxirfiately three turns. Again crank the en-
gine over to where the diaphragm (1) is pulled down in-
to mounting bracket (15) to its lowest position. Secure-
ly tighten the six head screws (3).
16. Mount fuel strainer to fuel inlet and connect fuel lines.
NOTE: The LQ-46, LQ-47 or LQ-46-A Repoir Kit c~d the pcJ~ts
included there-ln, which are Idendfled by an asterisk (*),
are the only parts of the fuel pump available for service.
Ref.
No.
No.
Description
Req.
* 1 DIAPHRAGM ........................................................
1
2
COVER SCREW ..................................................
I
3 SCREW, head to bracket mounting ....................
6
* 4 GASKET, cover (pulsator in LQ-47) ................
1
* 5 VALVE ASSEMBLY
............................................
2
* 6
GASKET for valve ..............................................
2
7 COVER ..................................................................
1
8
WASHER for cover screw ..................................
1
* 9 BUSHING for rocker arm p~n ..............................
1
"10 LINK for rocker arm ............................................
1
"11 SPRING for diaphragm ........................................
1
"12 SPRING for rocker arm ......................................
"13
PIN for rocker arm ..............................................
1
14
ROCKER ARM ....................................................
1
15
MOUNTING BRACKET ......................................
16
FUEL HEAD ........................................................
1
"17 GASKET for mounting flange ............................
1
27