Johnson Service Bulletin SB-820 (Revised) - Shifting Mechanisms

January 15, 1961

Bulletin No. SB-820 (Revised) Shifting Mechanisms

SUBJECT: Complaints of premature gear and shifter clutch dog wear; 1960 & 1961 V-75 engines.

FIGURE 1

Figures 1 and 2 illustrate some of many gears and shifter clutch dogs which were claimed to be prematurely worn because top edges of the ears are slightly, but insignificantly, rounded. The arrows in these two figures point to the worn ear edges; here represented by the short, slim highlights which invariably result from brightly polished metal surfaces caused by wear. This rounded condition is normal, and is not indicative of faulty material, parts or workmanship.

FIGURE 2

Rounding, or wear, of ear edges on gears and clutch dogs is a normal occurrence even though the operator's shifting practice is ideal; that is, smartly snap-shifting instead of attempting to ease into gear. Apparently many dealers analyze such ear wear as being the result of faulty parts, material and/or workmanship; particularly considering the many warranty claims received at the factory for replacement of such parts as are illustrated here. These parts were not faulty from a material or workmanship point of view and were therefore not really entitled to replacement under warranty.

Wear of gear and clutch dog ears can be very much accelerated by operators who possess the mistaken belief that gentle shifting (easing into gear) is the proper practice to safeguard the shifting mechanism and engine in general. This idea is particularly prevalent

in the minds of operators who are new and uninitiated to outboarding. Actually, the thought is totally erroneous because easing into gear causes the ears of gears and clutch dogs to rap and slide off their edges many times during one shift maneuver before gear engagement is finally accomplished. This repeated rapping-and-sliding-off process is the direct and principle cause of accelerated ear wear as well as a cause of their chipping.

FIGURE 3

Figure 3 illustrates a chipped ear on a clutch dog which was replaced under warranty. Since this clutch dog fully engaged the gear as intended, correct shift linkage adjustment is indicated; (note that the contact area, indicated by the highlight between the arrows on the upper, right hand ear, extends the full depth of the ear). Chipping is therefore believed to have been caused by the aforementioned rapping-and-sliding-off process of gear and clutch dog ears. Here, again, chipping is more indicative of faulty shifting practices by the operator than it is indicative of faulty parts or workmanship. This clutch dog, while not recommended for reuse due to the chipped ear, should have been replaced at the customer's expense rather than under warranty;

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SB-820 Page 2

particularly so since the stained appearance of this specific clutch dog also indicates it to have been used for a considerably longer time than the specified warranty period.

For correct shifting practices to be most effective, however, gearshift linkage adjustment on the engine must FIRST be as prescribed and illustrated in the V-4 Service Manual, Lower Unit Section, pages 113, 114 and 115. (Prior to making actual adjustments, first check the existing adjustment by following steps 4, 5 and 6 to determine if readjustment is necessary).

After a linkage check and adjustment has been made on the engine, be certain to also check adjustment of the knurled nut on the remote shift cable, if used, so the cable's locking plug aligns with the hole in the shift lever when in neutral position. Double-check this lock plug alignment in forward and reverse gears also, to be certain of full and complete gear engagement with remote operation.

The final step in reducing accelerated gear and clutch dog wear, is to advise your customers that the "DO-and-DON'T" rules of shifting Johnson outboard engines are these: 1. DO shift only at recommended idle speeds (600 r.p.m. ± 100). 2. DO smartly snap-shift (a quick, snappy movement of the gearshift lever to its full limit of travel). 3. DON'T shift above recommended idle speeds. 4. DON'T ease into gear. 5. DON'T slam into gear.

JOHNSON MOTORS

W. W. DeWees Service Department

WWD:eb

NOTE: Post on you V4 index - 75 H.P.

DESTROY SERVICE BULLETIN NO. SB-820 DATED DECEMBER 29, 1960.