22
23
PRIME VALVE
FIG. 24
STEP 1
:
Ensure that the pressure control knob (POT) is in the maximum (CW) position.
STEP 2
:
Remove the upper and lower clutch and electrical covers.
STEP 3:
Check all electrical connections between the engine magneto, sensor, control board and clutch for
loose connections or damaged leads. See Fig.25.
STEP 4
:
Disconnect the two leads from the control board (blue) and the clutch assembly (black). Using a mul-
timeter, with the engine at maximum RPM, pressure control knob in the maximum position and the prime valve
open (priming) position, test the DC voltage across the boards leads (blue). This voltage must be 13-14 VDC. If
the readings are correct, the board, sensor and magneto are okay and the problem is the clutch assembly. If this
is the case, proceed to Step 5. If the voltage is outside this range go to Step 7.
STEP 5:
Measure resistance between the clutch leads (black). This value must be 10-16 ohms. If this reading
is out of specifications the clutch is defective and must be replaced, otherwise continue troubleshooting.
STEP 6:
If the clutch resistance readings of Step 5 are correct, check the spacing between the clutch field
and plate. The gap should be .012” to .024”. If the gap is greater than .028 the gap is too wide. If this gap is too
wide, remove the spacer (Fig. 27, Item 4) from the clutch assembly. Should the clutch still not engage, replace
the clutch assembly. See page 25.
STEP 7:
When the DC voltage from the board is not 13-14 VDC, disconnect the control board lead (black) from
the engine magneto lead (pink), located on the side of the engine. With the engine at maximum RPM, pressure
control knob in maximum (CW) position and prime valve open (priming), read the AC voltage from the magneto
lead to the sprayer frame. This reading should be 19-24 VAC. If outside this range, contact your local Honda repair
facility for magneto replacement. If the magneto is producing the proper AC voltage, continue to Step 8.
STEP 8:
Test the sensor by reading the resistance between the red and black wires. The resistance runs be-
tween 1.5-3 kohms. A defective sensor usually shows no resistance (open). If the reading is outside standards,
replace the sensor. An alternative method to test the sensor, is to plug a new sensor into the board and see if the
clutch will engage. Caution! When using this method, ensure prime/pressure valve is in the prime position. This
is important because the sensor plugged into the board is not measuring pressure in the fluid section.
STEP 9:
When Steps 7 & 8 have been completed and the magneto and sensor check good, the electrical
control board is the only item left, replace the board. See page 24 in manual.
ELECTRICAL TROUBLESHOOTING
-Clutch Does Not Engage
1 117-046 Screw
2 115-063 Washer
3 115-072 Spacer
4 115-064 Belleville Spring (3)
5 115-065 Retaining Ring
6 115-067 Washer
7 115-071 Valve Stem
8 115-068 O-Ring Black
9 115-069 Ball
10 115-029 Valve Seat
11 115-012 Washer
12 115-073 Valve Body
13 115-074 Inlet Fitting
14 115-303 Handle with Label
PARTS LIST FIGURE 24
I
TEM
N
O.
P
ART
N
O.
D
ESCRIPTION
1
7
6
5
4
3
2
10
9
8
11
14
13
12