Hudson 1948 - 1952, Service Manual

Page: 42 / 333

2 - 22 ENGINE TUNE-UP
Twin Carburetors, set engine idle to 490510 with Hydra-
Matic, 540-560 for standard transmission and 575 for
Overdrive.
4. Normal setting is 1/2 to 1-1/2 turns open.
FIGURE 40
AIR CLEANER, GAUZE TYPE:
1. Remove the attaching wing nut and cover from air cleaner.
2. Wash air filter in kerosene and blow dry. 3. Re-oil with engine oil
and allow to drain and reInstall.
OIL BATH AIR CLEANER:
1. Loosen wing bolt sufficiently to allow the air cleaner reservoir to
be slid out from the bracket attached to the motor.
2. Remove cover and filter unit.
3. Wash filter unit in kerosene and blow out until partially dry.
4. Clean out old oil and sediment from cleaner reservoir.
FIGURE 41
5. Refill to oil level line with 50 S.A.E. engine oil for
temperatures above 32°F and 20 S.A.E. for lower temper-
atures. RPM- stall air cleaner, reversing procedure of
removal.
COMBUSTION ANALYSIS :
1. Start engine and warm up to normal operating tempera-
ture.
2. Calibrate combustion tester as outlined in " Equipment
Manufacturer's Instruction Manual".
3. Connect the Vacuum Pressure Gauge hose, Tachometer-
Dwell leads and exhaust unit of the Combustion Tester
as shown in Figure 41.
4. The correct reading for combustion efficiency and perfor-
mance at an idle speed of 540-560 R.P.M. (490-510 on
cars equipped with Hydra-Matic) should be 70%, plus or
minus 3% with a peak manifold vacuum. Adjust idle
adjusting screws as necessary.
NOTE: If the above reading cannot be obtained, it indi-
cates internal faults of the carburetor provided compres-
sion and ignition are satisfactory
.
5. Increase the engine speed to 2000 R.P.M. and check
the test meter reading which should now read 85%,
plus or minus 5%, proceed as follows:
a. Remove the air cleaner and see if the additional air
entering the carburetor corrects the reading. If it does,
it indicates some restriction in the air cleaner.
b. If the mixture still shows rich with the air cleaner
removed, it indicates trouble in the carburetor.
6. With the engine operating at. 2000 R.P.M., advance
and release the throttle quickly. The combustion meter
reading should move toward "Rich" 10% or more if the
accelerating system is operating properly. If no move-
ment is noted, the trouble may be due to an improper
pump stroke setting, worn linkage, bad pump leather
or leaking pump inlet or discharge check valve.
7. Pull the exhaust hose off the panel fitting and allow
the booster to continue running in order to dry out the
unit.
NOTE: Always drain excess water from the exhaust hose
and gas pickup unit after each test.