Service Bulletin 2-18 Cam Case Gears – 149-249 Model

SUBJECT: CAM CASE GEARS – 149- 249 MODEL

Two types of cam case gears he.ve been assembled in the 149- 249 model engines.

Model 149 engines with numbers ADI-1001 to ADI-3485 were assembled with 20° tooth pressure angle gears.

Model 149 engines with numbers ADI-3486 and up were assembled with 14-1/2° tooth pressure angle- gears.

There were a few 149 models be tween ADI-1001 and ADI-3485 that were equipped with the 14-1/2° tooth pressure angle gears but we do not have a record of the engine numbers.

Model 249 engines were assembled with 20° tooth pressure angle gears with the exception of a very few machines. We do not have a record of these engine numbers either.

The two different types of gears can be identified by observing their finish —

1. The 20° tooth pressure angle gears are not plated, so they are natural steel color.
2. The 14-1/2° tooth pressure angle gears are cadmium plated, so they are white or silver colored.

The sketches on the next page show the easiest, most positive method of identifying the two types of gears in case they become discolored and cannot be identified by the finish.

A 1/16″ diameter wire or drill can be rocked between the teeth of the cadmium plated gears (14-1/2°) but will be tight between the teeth of the unplated gears (20°).

NOTE: The generator gear and the fiber or replacement steel gear (1462015) are all the same type with the 20° tooth pressure angle.

IMPORTANT

If, for any reason, it becomes necessary to replace any gear in the cam case, other than the generator gear and the fiber or replacement steel gear, you must clean the gear or gears thoroughly and observe the finish or check with
a wire or drill to determine which of the two types of gears must be used for a replacement.

CAUTION

If two different types of gears are assembled in the same cam case, the result will be a loud whine or grinding noise and eventual damage to the mismatched gears and bearings. Both types of gears are available from your Parts Distributor or our Parts Department, but be sure to order the correct type to match up with the other gears in the original set.

Part numbers for the unplated 20° tooth pressure angle gears, as assembled in the 149 Models ADl-1001 to ADI- 3485 and most ell 249 models, are:

Part numbers for the cadmium plated 14-1/2° tooth pressure angle gears, as assembled in 149 models ADI-3486 and up and a few 249 models, are:

Part numbers for the two gears that have the 20° tooth pressure angle (unplated), and are the same type in all engines assembled, are:

1462015 Generator Idler Gear (steel) replaced fiber gear #1462002
1462001 Generator Gear

Walter Brown
Service Manager