Chevrolet with Old Carter Carburetors : 1941 Chev. 1941 G.M.C. 1942 Chev.Previous | Home | Next |
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Form 6500—Canadian
CHEVROLET 4895-517S May, 1942
SERIAL NUMBERS
489S
1941 Chev.
1941 G.M.C.
1942 Chev.
BB UP-DRAFT CARBURETER Nos. 489S-517S—LIST PRICE $22.05
A $2.50 exchange allowance is deducted from the list price if buyer turns in
carbureter which is replaced by a 4895.
CARBURETER SPECIFICATIONS
For Chevrolet Six-Cylinder Engine (31/2-inch Bore, 33/4-inch Stroke)
Dimensions: (Both) Flange size, 11/4 inch (31.75 mm). (489S) Throttle bore, 1-7/16
inch (36.51 mm).
(517S) Throttle bore, 11/2 inch (38.10 mm).
(4895) Main venturi, I inch I.D. (25.40 mm).
(517S) Main venturi, I-I/16 inch I. D. (26.99 mm).
(Both) Air bleed through venturi, to idle passage .0885 to .0905 inch diameter
(2.25 to 2.30 mm) drill.
Float Setting: (Both) Top of float 1/32 to 1/16 inch (.79 to 1.59 mm) below top
of surface of lower body.
Balance Vent Tube: (Both) Inside diameter, 7/32 inch (5.56 mm). Restriction hole,
in upper body, size 5/32 inch (3.97 mm) diameter.
Gasoline Intake Needle: (Both) Triangular, horizontal. No. 38 (2.58 mm) drill
in needle seat.
Idle Jet Tube: (Both) Jet size, .0236 inch (.60 mm) drill.
Idle Ports: (Both) Lower port size: .062 to .064 inch (1.58 to 1.63 mm) diameter.
Top of port located .005 to .009 inch (.13 to .23 mm) below lower edge of valve.
Upper port size: .053 to .057 inch (1.35 to 1.45 mm) diameter (for idle adjustment
screw).
Set Idle Adjustment Screw: (Both) V2 to 11/2 turns open. For richer mixture,
turn screw out. Do not idle engine below 300 r.p.m. or 6 m.p.h.
Main Metering Screw: (4895) Calibrated to flow 268 to 272 cc per minute.
(5175) Calibrated to flow 366 to 370 cc per minute. (Do not gauge for size. If
in doubt, replace with new part.) Nozzle: (489S) No. 33 (2.87 mm) drill, I. D.
(30°).
(5175) No. 33 (2.87 mm) drill, I. D. (24°).
FOR READINGS BELOW, VIEW CARBURETER FROM SIDE OPPOSIE AIR INTAKE
Choker: (Both) Buttery type, with compensating air valve. Lever mm); when open,
points up.
on left side. Throttle Lever Adjustment: (Both) On left side.
Throttle Lever: (Both) On right side, length 11/2 inches (38.10 Tube Clamp: (Both)
On air intake—left side.
Motor Tune-Up—Be Accurate! Always Use Feeler Gauges!
CAUTION: Change worn or leaky flange gaskets. Tighten manifold bolts and test
compression before adjusting carbureter.
CHEVROLET &
G. M. C.
CAB-OVER-ENGINE
TRUCK
1941-42
Accelerating Jets: (4895) 2—.0394 inch (1.00 mm) drill 1/16 inch (1.59
mm) from shoulder.
1—.051 inch (1.3 mm) drill 3/8 inch (9.525 mm) from shoulder. 1—.063
inch (1.6 mm) drill 23/32 inch (18.256 mm) from shoulder.
1—.051 inch (1.3 mm) drill I-I/16 inch (26.99 mm) from shoulder.
(517S) 2—.038 inch (.97 mm) drill 1/16 inch (1.59 mm) from shoulder.
2—.038 inch (.97 mm) drill 3/g inch (9.525 mm) from shoulder. 2—.038
inch (.97 mm) drill 23/32 inch (18.256 mm) from shoulder.
2—.038 inch (.97 mm) drill I-1/16 inch (26.99 mm) from shoulder.
Air Bleed to Nozzle: (489S) (Vent tube) Size, .0394 inch (1.00 mm) drill.
(5175) (Vent tube) Size, .048 inch (1.22 mm) drill.
Step-up Jet: (489S) (Power Orifice) Size, .038 inch (.965 mm) drill.
(5175) (Power Orifice) Size, .055 inch (1.40 mm) drill.
Accelerating Pump: (Both) Type, low pressure, delayed action. Stroke: Summer
setting, inner hole, short stroke 9/ 16 inch (14.29 mm). Winter setting (outer
hole, long stroke) I inch (25.40 mm). Pump intake ball check: Size 1/8 inch (3.175
mm). Pump discharge retainer (in pump valve cage assembly) .0635 inch diameter
(1.615 mm) drill size.
Vacuum Spark Port: (Both) Slot type, .041 x .125 (1.041 x 3.175 mm). Top of port
.000 to .004 inch (.0 to .1016 mm) below valve.
Spark Plug Gap .040"
Set
Breaker Points
.018"
Use Neon Timing
Light or Timing Light Breaker Points to open 5° before top dead center
Correct Float Level
1/32" to 1/16"
Below Edge of Casting
(Remove Gasket)
fo\
Set Valves
Hot
Intake .006" to .008"
Exhaust .018" to .020"
Copyright 1942
by Carter Carburetor Corporation
All rights reserved.
CARBURETER ADJUSTMENTS
should be connected in inner hole, giving short stroke. If this does not give
desired results, the main metering jet, pump metering jet, check valve assembly
and pump valve assembly should be removed and cleaned with compressed air.
If Motor Loads—Check Float Level: Wear on lip of float lever will raise
float level from factory setting, causing carbureter to load up. To lower float
level, bend lip of float lever toward needle. To raise float level, bend lip
away from needle. A very slight bend is sufficient. Be sure to bend lip of float,
not bracket.
To Secure a Good Idle: Set throttle lever adjusting screw so motor runs approximately
300 rpm. Then set idle adjustment screw so motor fires evenly. Correct setting
will be found between 1/2 and 11/2 turns open. A richer mixture is obtained
by backing out adjustment screw—a leaner mixture by turning screw in.
If motor stalls while idling, remove idle passage tube and idle jet tube and
clean with compressed air.
To Improve Acceleration: Examine pump link setting: For winter driving, link
screw should be set in outer hole, giving long stroke; for hot weather, in
high altitudes, pump link