CONTACT POINT PRESSURE.

Table 5. The point opening of new points can be

2 . Check engine breather pipes, since clogged

checked with a wire feeler gauge, or a Dwell Angle

pipes cause crankcase pressure which will force oil

Meter. A meter of this type indicates the cam or

up into the distributor.

contact angle. This angle is the number of degrees

t h a t the breaker cam rotates from the time the

3. If the advance mechanism of the old

points close until they open again. The cam angle

distributor was found to be worn, check the engine

increases as the point opening is increased.

for worn oil pump gears, since these cause backlash

Manufacturers of this type equipment furnish

which produces torsional vibration; such vibration

c o m p l e t e instructions as to their use. Refer to

causes rapid advance mechanism wear.

Table 5 for dwell angle.

4. Be sure to install the new distributor all the

5-75. CONTACT POINT PRESSURE.

way down in its mounting well. If the distributor is

not pushed all the way down, the distributor shaft

The contact point pressure should be checked with

is apt to freeze in the distributor housing and cause

a spring gauge. The scale should be hooked to the

complete destruction of the unit.

breaker lever and the pull exerted at an angle of

90 degrees with the point surface. Reading

5. Be sure that unit is properly timed, as shown

should be taken just as points separate. The

in figure 5-68.

pressure can be adjusted by bending the breaker

lever spring. If the pressure is excessive, it can be

5-77. CARBURETOR.

d e c r e a s e d by pinching the spring carefully. To

increase, the lever must be removed from the

5-78. REMOVAL.

distributor so the spring can be bent away from the

lever. Avoid excessive spring distortion. New

a. Remove cotter key from accelerator rod at

breaker lever springs may be stronger than required

throttle arm and pull rod from throttle arm hole.

in service; be sure to check the spring tension of all

new levers when installed. Remember that

b. Remove the air cleaner to the carburetor hose.

excessive pressure causes rapid rubbing block, cam,

and contact point wear while insufficient pressure

c. Disconnect choke control.

will permit high-speed point bounce which will, in

turn, cause arcing and burning of the points and

d. Disconnect fuel pump to carburetor line.

missing of the engine.

e. Remove two nuts and lockwashers at the

Breaker lever spring tension should be 17-21

manifold to carburetor flange and withdraw

ounces when measured at the center of the contact

carburetor from machine.

or 19-23 ounces when measured just behind the

contact. The tension may be measured with any

5-79. DISASSEMBLY. (See figure 5-81.)

suitable spring gauge, provided the pull is exerted

at 90 degrees and the reading taken just as the

Disassembly of the carburetor is not recommended

points begin to separate.

except by

experienced

mechanics.

The

disassembled view will identify the various

The distributor should be tested on a distributor

component parts and show their relation to

tester that will check the centrifugal advance

a s s e m b l y . Use the disassembled view with the

mechanism.

i d e n t i f y i n g part numbers to identify and locate

parts when performing the disassembly and

5-76.

REINSTALLATION.

reassembly operations.

When installing a distributor, observe the following

A . REPAIR PARTS.

cautions:

Refer to the parts section of this manual for

1. Be sure the distributor mounting is clean so

carburetor repair kits. The use of the proper repair

t h e r e will be a good ground connection for the

parts kit is essential in the event repair is to be

distributor.

performed on the carburetor. The following

5-53