Yamaha 20C Owner's Manual

Also see for 20C: Service manual Owner's manual

3-8EMF50011BREAKING IN (RUNNING IN)ENGINEYour new engine requires a period ofbreak-in (running-in) to allow mating sur-faces of moving parts to wear-in evenly.Correct break-in (running-in) will helpensure proper performance and longerengine life.cCFailure to follow the break-in (running-in)procedure may result in reduced enginelife or even severe engine damage.EMU00226Run the engine under load (in gear with apropeller installed) as follows.1) First 10 minutes:Run the engine at the lowest possi-ble-speed. A fast idle in neutral isbest.2) Next 50 minutes:Do not exceed half throttle (approxi-mately 3,000 r/min). Vary enginespeed occasionally. If you have aneasy-planing boat, accelerate at fullthrottle onto plane, then immediatelyreduce the throttle to 3,000 r/min orless.GBBreak-in (running-in) time:10 hoursBreak-in (running-in) premix ratio:Refer to “Gasoline/Petrol and Oil Mixing”.