February 9, 1959

SERVICE BULLETIN #692

CHECKING EXHAUST HOUSING AND UPPER GEARCASE ALIGNMENT

Recently a number of complaints have been received con- cerning broken driveshafts, worn or stripped driveshaft and crankshaft splines, and premature gear failures.

Investigation of these complaints have revealed that in most cases, misalignment of either the gearcase or exhaust housing, as the result of an accident or the striking of an underwater object, has caused one or more of the above complaints.

Illustrated are two methods of checking for housing alignment.

When checking for alignment with a drill press, as illustrated, use the following procedure.

Set the housing to be checked on the drill press table and lower the chuck, with the jaws closed until a very light contact is made on the flat machined surface of the housing. Lock the drill press arbor in this position, so that the chuck cannot move up or down. Move the flat surface of the housing under the jaws, and follow the surface around to the starting point. If the housing is in perfect alignment, the clearance between the chuck jaws and the housing flat surface will be the same at all points. If there is any difference in clearance between the chuck jaws and the housing at any point, the housing is out of alignment and should be discarded.

NOTE: Both top and bottom housing surfaces must be parallel to one another for a perfectly aligned casting.

If a drill press is not available, a surface plate and dial indicator may be used as illustrated in Figure 2.

Very truly yours,

JOHNSON MOTORS

Jack Penland Service Department