Keep It Running

Most small engines that land in a repair shop aren't worn out. They're full of stale fuel, running on dirty oil, or choking on a clogged air filter. Written by a certified small engine mechanic, this guide covers the handful of jobs that keep air-cooled four-strokes and two-strokes running for decades, plus a step-by-step annual tune-up, a no-start troubleshooting flowchart, and a printable maintenance record.

What's inside

1. Why maintenance matters
2. Safety first
3. How a small engine works
4. Tools and supplies
5. Fuel, ethanol and two-stroke mix ratios
6. Oil
7. Air filter service
8. The spark plug
9. The carburetor
10. Cooling, valves and compression
11. Starter, governor, blades and belts
12. The annual tune-up, step by step
13. Troubleshooting
14. Seasonal storage
15. Maintenance schedule and record sheet
16. Glossary and resources

Download the PDF

© 2026 Steve Spence. Shared under CC BY-NC 4.0: copy, share and adapt it for non-commercial use with credit to Steve Spence and a link to kk4hfj.com. Please don't sell it.