I bought a lawnmower that has these oil change service intervals in the engine operating manual:

  • After the first month or after 5 operating hours: change the engine oil
  • Every 6 months or after 50 operating hours: change the engine oil

The trouble is, I use the lawnmower only 4 hours during a year during the growing season (which lasts about 3 months per year here). So the subsequent oil changes would happen approximately once every 12 years if I followed the operating hours interval. That I'm not going to do, so I think an oil change every year or two is useful. An oil change every 6 months doesn't make any sense since the lawnmower is not used during the winter, so half of the oil would remain completely unoperated. But if the lawnmower is not used for more than a half of the year, skipping one of the two yearly oil changes probably follows the manufacturer's instructions closely enough, if not exactly to the letter.

However, what should I do for the first oil change? I don't want to waste my time running the lawnmower needlessly to accumulate the 5 operating hours in a month, and not wasting my time and using a zip tie to run the machine idling would probably be somewhat unsafe. So I have to decide a proper time for oil change based on the conditions in which I actually use it.

One possibility is to just ignore the break-in oil change and do it according to the usual oil change service interval (which would be two oil changes per year if used around the year; if not, only one oil change per year slightly bending the rules). Then I get nearly 5 operating hours of usage at the time of the first oil change, but far more than a month of usage then.

Another possibility would be to change the oil right now. There's little over 2 hours on the machine right now and little over month of use.

  • 1
    I think just about any answer you get is going to be opinion here. There is no definitive. That said, it is my "opinion" you should run your mower for however long you are going to run it the first year, then just before you use it the next year, change the oil. Then, do the same thing ever year. At the start of the new mowing season, change the oil. Again, JMHO. May 21, 2023 at 12:59
  • I think paualster2 response should be considered an answer. His advise covers all requirements for proper oil maintenance. Just use the recommended oil and change filter if equipped at recommended intervals.
    – Jupiter
    May 21, 2023 at 14:10
  • I have had several B&S engined motor mowers. I never changed the oil, ever. The mowers deceased for other reasons, after about 10 years use. From the capital expenditure that equates to about 50 pence per week. May 21, 2023 at 19:03
  • "the lawnmower is not used during the winter" but mineral oil degrades with time. May 21, 2023 at 19:11

1 Answer 1


I agree with Paulster2. I have 2 riding mowers an old Craftsman L1000 & a newer 8 yrs old Deere D140. I change the engine oil once a year when it's time to mow. Between the two machines I have logged over 2500 hrs in almost 20 years with no issues. I personally find it beneficial to run them out of gas before storing and I put the batteries on trickle charger. Doing this way I have had no issues with the carb getting gummed up from stale fuel and still using the original batteries in both. Other than that both machines have been great. Worn out a deck drive belt or two and I believe a starter solenoid (normal wear items IMO). Hope this helps.

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