Honda C65 - Adjusting the Slow Speed; Adjusting the Idle

3.7 CA RBUR ET OR
43
~ ::ssi e black exhaust smoke is evid ent
--e - ed i ate s pee d, it is an indi cat ion
:: -i::- a fuel m ix ture and theref o re, th e
="" -:e:: e hould be lo were d one step.
=- -· -g ac~eler a tio n o r at in termediate speed,
-e e"gin e sputters, miss es or doe s not respond,
--e 'e nee dle sho uld be raised o ne step.
---:::-le valv e cut -a w ay. (Fig. 3- 1 04)
- e l arger th e number stamped on the cut-awa y,
eaner will be the fuel mi xture. Wh en making
he adjustment of
th e th ro ttl e valve, the sl ow
sp eed should also be co nsid ere d t oge ther with
the in
termed i ate speed si nce the effec ti ve rang e
of the thr o ttle is very br oad .
c. Adju st ing th e Slow Speed
The fuel mixt ure ad justment bet w een i dli Ag and 78
hrott le o pening is made by the air screw and the
hro ttle valve cut- awa y.
(l l Ai r sc rew
The fuel mixture adju stment for idling is made by
the air s crew.
Tu rn to th e right fo r a richer mixture. Turn to
the left for a le aner mi xt ure. The air sc r ew not
only
aff ects the idlin g but al so the slow sp ee d,
the r ef o re, the fuel mi xt ur e sh ou ld be adjusted
with the thr
ottl e sli ght ly o pe n ed to o btain a
sm
oo th op er at io n.
!2 1 Th ro tt le valv e cut- awa y
Th ere may be a case wh ere the ad jus tm ent c an -
no t be o bt ained by the air screw o nl y, in the
vicinity o f 78 th ro tt le ope ning. In this case, if
the fuel
mi xture is t oo rich, rep la ce the cut- awa y
wit h one of a l ar ge r number and if t oo lean,
r
ep la ce with o ne of a smaller n um ber .
d . Ad j usting th e Idle (Fig. 3- 105, 3- 106)
The id ling ad ju stment is pe rfo rm ed by the th ro ttl e
s
top sc rew and th e air screw in th e fo llo wi ng manner.
( ll Adjust the idli ng sp ee d to the s ta n dard 12 00
RPM by the use of th e thr o tt le sto p sc rew .
!21 N ext, turn the a ir sc r ew sl ow ly back and forth
to
th e hi ghest RP M.
( 31 U pon l oc at ing the po int o f highest RP M in (2)
above , reset the engine speed to th e s tandard
RPM .
( 4) Rework th e a ir screw to ass ure that it is set at
the
pro per setting.
(5) If any ch ange exist, repeat (3 ) !41 above . The
check should
be m ade betwee n 78 to 1 }6 turn
of
th e air sc r ew.
Cut-Aw ay
S ep po si tio n
I
J et need le
Figure . 3- 104.
Je t needle and cut -awa y of th e th rottle
v al ve
Thrott le st op
'
Fig ur e 3- 105. Idle adj us tment
Fi gure 3- 106. Idle adjustment !S50, S65)