Rebuilt Powerhead Break-in Procedures

The first 10 hours are the most important hours of your new 2-stroke Mercury, OMC, and Yamaha life.

Engine Oil & Fuel

• Double the oil quantity with an approved non-synthetic TCW-3 oil.

• Increase fuel mixture to rich

• Use 91 to 93 octane premium fuel or higher for high compression heads.

• Avoid products that have alcohol additives, or chemicals that may alter the fuel condition.

Initial Break-in & Warm-up

• Allow for four (4) hours for break-in of a new piston and/or rings at idle speed, keeping the engine under 3,500 rpms.
  

• For the first 10 hours, avoid continuous full throttle.
  

• Ensure the engine reaches normal operation temperatures to avoid cold seizure that results from the piston expanding faster than the cylinder liner (which is being liquid-cooled).

RPM Guidelines

• For hour five (5), after warm-up, operate the engine in gear at approximately 1,500 RPM for the first twenty minutes.
  

• For the remaining forty minutes, operate the engine in gear no more than three thousand RPM.
  

• Use only enough throttle to plane the boat, then immediately throttle back to less than three thousand RPM.
  

• For the sixth hour, accelerate enough to bring the boat up on the plane quickly, and bring the throttle back to maintain the boat up on the plane.
  

• During this period, vary your engine speed by accelerating to 3/4

• throttle for a minute or two, then back to minimum planning speed.
  

• Do NOT run at constant RPM for prolonged periods.
  

• For the next four hours of operation, continue to cruise at approximately 3/4 throttle or less at minimum planning speed.
  

• Occasionally reduce the throttle to idle speed for the cooling period. During the final hours, you may operate the boat at wide open throttle for periods of less than two minutes.

These are general break-in procedures that may vary from OEM guidelines and our race program.

Always refer to the OEM service manual for the most model-specific break-in procedures and guidelines.