1971 Johnson 60HP outboards Service Manual, Page 55Get this manual
BREAK-IN
Be sure that when an engine is returned to service after an overhaul, the owne, is advised to follow break-in procedures exactlySee inside front cover and page 2-6 for correct fuel mixtureFor the first to 10 minutes, operate engine at fast idleCheck operation of water pumpFor remainder of first hour, do not operate engine over 3000 rpm (approximate) or one-half throttle (approximate)
With easy planing boats, it would be desirable to bring the boat into planing position with full power and then immediately reduce the throttle setting to approximately 3000 rpm (one-half throttle)BE SURE boat maintains planing attitude at this throttle settingDuring second hour, bring boat into planing attitude and reduce power to 4000 rpm (approximate) or three-quarters throttle (approximate), while maintaining planing attitudeAt intervals during the second hour, apply full power for periods of one to two minutes, returning throttle to original setting (4000 rpmthree-quarters throttle)Avoid continuous full throttle operation for extended period during the next few hours"