February 28, 1961
Bulletin No. SB-830
Flywheel-Magneto
SUBJECT: STRENGTHENED FLYWHEEL;
35 H.P. models RD thru RDSL-21B (1959);
40 H.P. models RD thru RDSL-22 & 23 (1960 to date).
Figure 1
Figure 1-A illustrates the forged, steel hub
which has been cast into flywheels for model
series RD’s since 1959. This improved hub
was first used on 35 h.p. production models
RD through RDSL-21B. Because this hub provides
strength superior to any previously used, it
is still utilized on current production engines
as well as in flywheels intended for servicing
engines in the field.
Flywheels using this forged, steel hub fre-
quently develop hairline cracks between the
puller screw holes on the underside, figure
2, over. However, these very small cracks
exist only in the aluminum cast around the hub
or its flanges! Because the steel hub is the main source of strength, these hairline
cracks should be ignored since they do not, in any manner, affect the flywheel’s
strength, durability or efficiency.
Because identification of flywheels using this forged, steel hub became necessary when
first introduced, the letter "Q" was, and still is, cast into the aluminum at the rope
notch provided for emergency starting, figure 1-B. If hairline cracks appear on any
flywheels so marked, do NOT request replacements. These minuscule cracks do not, by
themselves, justify replacing flywheels under warranty or otherwise.
We have received reports that many dealers are using the type of flywheel puller which
grasps the outer rim of the flywheel. Such pullers must not be used because they exert
undue strain on the flywheel’s hub. A Johnson recommended puller, part #378103, can
be purchased from Outboard Marine Corporation’s Parts Depot, Galesburg, Illinois, for
$9.50 net. This puller is specifically designed to pull our flywheels, and if properly
used, will do the job without flywheel injury.
JOHNSON MOTORS
W. W. DeWees
W. W. DeWees
Service Department
WWD:eb
NOTE: Post on your RD index - 35 & 40 H.P.
Destroy service bulletin SB-727 dated 7/27/59.
OVER
