Johnson Service Bulletin SB-901, Revision 2 - Torque Tension Chart

Proper torque tension on screws, nuts and bolts is extremely important when servicing Johnson outboard engines. Over-torquing can warp castings and create a friction bind or a water leak in an engine. Over-torquing may also result in stripped threads which increases labor costs when having to drill, re-tap and install a heli-coil.

Screws left loose are apt to back out. Internally, such screws will cause extensive damage to the powerhead and/or gearcase. Externally, loose screws invite leakage at gaskets or between crankcase halves, etc.

Needless to say, the only certain and recommended method of properly tightening screws is by using a torque wrench. These wrenches are readily available and may be purchased at reasonable costs from local parts houses, tool jobbers and mail order houses. They will rapidly pay for themselves in expert workmanship.

Fig. 1

When torquing surfaces such as cylinder heads, exhaust covers, intake manifolds, etc., always follow the recommended sequence illustrated in Figure 1. Start at the middle and work evenly towards each end in a circular motion.

These apply to all engines unless otherwise specified under the individual engine specifications contained on the reverse side.