October 23, 1958
SERVICE BULLETIN NO. 680
SUBJECT: LEAF VALVES AND STOPS - ALL MODELS
In the event the occasion arises making it necessary to dis-
assemble the leaf plate assembly, care should be exercised in
handling the leaf valve and leaf stop. Under no circumstances
bend or flex the segments of the leaf valve or do not attempt to
increase the degree of leaf opening by bending the fingers on
the leaf stop.
The segments on the leaf valve are designed and heat treated to
flex just so much during the crankcase suction stroke. If
flexed beyond the critical point of design, metal fatigue break-
age will result.
Whenever it becomes necessary to replace the leaf valve, we
strongly recommend you also install a new leaf stop to eliminate
the possibility of a repeat failure.
JOHNSON MOTORS
Walter McCleod
Service Department
WM/aks