While most Outboards Do not Have a Hour meter, I understand they can be easily installed On a Message Board, Someone Suggested Keeping Track of How Much 2 Cycle Oil you use. ( Of course this applies to 2 stroke engines only) On PreMix Systems(OIL Added Directly To Gas) Ratio is 50:1 on Oil Injection it is approx The Same.. You can approximate How Much Gas You Burn over a period of time and get an idea of How Much a Motor is used... I also heard that a typical recreational boater has approx 50 Hours per season on a motor.
I installed an hour meter. Cost about $40 from BPS or Cabellas. Connected it to the ignition switch. When the key is on the motor is running and the hour meter is also running. Took about an hour to install complete. That way you don't have to guess.