Hudson 1948 - 1952, Service Manual

Page: 22 / 333

2 - 2 ENGINE TUNE-UP
ENGINE TUNE-UP
Modern high compression, high speed engines require
periodic diagnosis and adjustments to maintain peak perfor-
mance and economical operation. A periodic engine tune-
up will assure this maximum engine performance, fuel
economy and dependability.
Accurate testing equipment in good condition is essential
to proper diagnosis. If a master tester is used, the battery of
the tester should be maintained in a fully charged condition.
The tune-up procedure is arranged in the usual order of
performance. Only by performing the operations in the
following procedure and adhering to the limits and specifi-
cations given therein is it possible to obtain the maximum
performance and economy built into Hudson engines.
BATTERY
Many of the tests involved in tune-up are dependent upon
a battery in good condition. If the battery is below standard,
it should be recharged, or replaced with a fully charged
battery before the tune-up.
BATTERY SPECIFIC GRAVITY:
Check the battery specific gravity with a hydrometer,
Figure 1. A battery when fully charged should show 1.270
specific gravity at 70° F. A uniform hydrometer reading
below 1.225 at 70° F. indicates a low battery that should be
recharged.
FIGURE 1
If gravity varies more than 25 points between cells, battery
should be recharged and tested under load.
CAUTION: Electric storage batteries give off highly in-
flammable hydrogen gas when being charged and con-
tinue to do so for some time after receiving a steady
charge. Do Not allow sparks or an open f la m e near the
battery, especially in the vicinity of the battery vent caps.
Before doing any work around the battery, a metallic
contact between the car bumper and the ground should be
made to remove any possibility of a static charge causing
a spark in the vicinity of the battery.
BATTERY LOAD TEST:
Battery may be tested under load by connecting a voltme-
ter across the battery terminals and cranking the engine.
Battery is satisfactory if it will crank the engine at a good
speed for 1/2 minute and the voltage does not fall below
4-1/2 volts. Slow cranking speed or lower voltage may be
due to high resistance in the starter circuit. Check cables and
retest. (DO NOT CRANK MORE THAN 1/2 MINUTE
AT A TIME ).
A standard cell tester may be used to make the load test.
The cell tester has a shunt across the terminals which places
each cell, under load. Each cell should show 1-1/2 volts or
over, and the variation between cells should not exceed .15
volts.
FIGURE 2