Onan MCCK - VACUUM-BOOSTER ADJUSTMENT

VaciMia-Booster Adjustment: After satisfactory perform¬
ance under various loads is attained by governor ad¬
justments without the booster, connect the booster.
Connect the booster external spring to the bracket on
the governor linkage. With the plant operating at no
load, slide the bracket on the governor linkage to a
position where the external spring is just free from
tension.
Apply a full rated electrical load to the generator. The
output voltage should stabilize at nearby the same read¬
ing at full load as for no-load operation. The speed may
remain about the same, or increase when the load is
applied, resulting in 1- or 2-cycle frequencies higher
than the no-load frequency. (1 cycle is equal to 30 rpm
for a 4-pole generator.) If the rise in frequency is more
than 2 cycles, lessen the internal spring tension. If
there is a drop in frequency, increase the booster inter¬
nal spring tension. To increase tension, pull out on the
internal spring bracket and move the pin to a different
hole.
With the booster disconnected, a maximum drop of 5 cy¬
cles from no-load to full-load is normal. Witli the boost¬
er in operation, a maximum increase of 2 cycles from
no-load to 2/3 load is normal. A drop of 1 cycle at 1/4
load is permissible, giving an over-all maximum spread
of 3 cycles.
AMBIENT TEMP. <°F)
60
65
70 75
80
85
90 95
100
CHOKE OPENING (Inches)
l/B 9/64
5/32 1 1/64
3/16
13/64
7/32 15/64
1/4
-CHOKi OPENING
(Set »*xt)
- //V
r \
CHOKE PLATE
Gi — iCi
N ^-LOOSEN THIS
- H i
SCREW AND
— - Hi
f ROTATE THE
-o
ENTIRE COVER
ASSEMBLY
Figure 22. Thermo-Magnetic Choke Adjustments
INTERNAL SPRING-
BRACKET f—
VACUUM
BOOSTER-
THIS
DISTANCE
DETERMINES
SENSITIVITY
| 1
I MORE
| SENSITIVE [
L LESS i
SENSITIVE i
CARBURETOR
THROTTLE ARM-
CARBURETOR
THROTTLE
PLATE—V _J
MOUNTED ON TOP GOVERNOR
ON SPEC “B” LINKAGE-
AND "C”
-GOVERNOR
SPRING BRACKET
V GOVERNOR
_. JXi SPRING
-EXTERNAL
SPRING
‘GOVERNOR
ARM
GOVERNOR
SHAFT
-SPRING
ADJUSTING STUD
GOVERNOR ADJUSTMENT
Figure 23. Governor Details.