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Basics of Small Equipment Maintenance

Curtis McKittrick, Soils & Plants Technician

Safety: Dealing With Noise

  • Earplugs are a must.
  • Goggles are a must for any equipment that generates dust or sparks.
  • NEVER run power equipment indoors without hearing protection!

Safety: Other Considerations

  • Goggles are a must with any equipment that generates dust or sparks.
  • Gloves are highly recommended with all handheld power equipment, because they help to mitigate the effects of vibration (Industrial White Knuckle Syndrome, a permanent lifelong disorder).

What Equipment Do I Buy?

  • First question: How much money does it make you?
    • Most OPE manufacturers offer two or more "grades" of equipment.
    • For high-intensity applications, commercial equipment will hold up better, is more ergonomic, and usually offers features that improve productivity.
    • For capital planning purposes, handheld power equipment has a useful economic lifespan of 1,000 engine hours or 10 years, whichever comes first.
    • EPA compliance labels are not lifespan information

Performance Considerations: Trimmers

  • 20–25cc for turf use
  • 30cc and up for farm use
  • Bump-feed head
  • Solid, straight shaft for farm use

Performance Considerations: Chainsaws

  • 25–40cc for pruning and home use
  • 45–65cc for general farm use
  • 10–16" bar for pruning and home use
  • 1–24" bar for general farm use
  • Laminated vs. solid bars

Saw Chain

  • Most chainsaws are originally equipped with "low-kickback" chain.
  • Not all chain is low-kickback.
  • Full-Complement, Skip, 0.5 Skip.
  • Chisel for softwood and clean conditions.
  • Semi-chisel for hardwood and dirty conditions.
    • Note: Most of us are working in suboptimal conditions.
    • Note: If you are new to hand-sharpening, avoid Chisel chains.


Fuel Selection

  • Use 87 Octane motor fuel, as with an automobile.
  • Higher-octane fuels have lower volatility and make starting harder.
  • Power equipment engines do not have a high enough compression ratio to benefit from high-octane fuel.

Fuel Storage

  • Must be stored in sealed containers!
    • Put the spout back.
    • If cans are equipped with vents, close them.

What About Ethanol?

  • Properly handled, ethanol causes no problems in modern power equipment.
  • Most problems with ethanol relate to its hydrophilic properties.
  • Many problems blamed on ethanol are caused by emissions-compliant carburetors- this is a problem in itself, but cannot be worked around by using ethanol-free fuels.

What Ratio Should I Mix Fuel At?

  • 50:1 by default.
  • Use oil rated for air-cooled engines.
  • DO NOT use boat engine oil.
  • Other mixtures can be used if the carburetor is re-tuned.
  • Engines manufactured prior to 1980 may run slightly better with the recommended 25:1 or 16:1 mix, but will perform satisfactorily with 50:1.

Remember: Keep containers sealed!


Remove the spark plug wire.


  • Remove blade with wrench and hammer.
  • A wood block may be used to lock crankshaft.
  • Use a bench grinder or angle grinder.
  • 45–60 degree angle.
  • Remove the spark plug wire and secure it out of the way!


  • Check rakers first, because the file often hits the cutter edge.
  • 0.010 gap between raker top and cutter tip.
  • When sharpening cutters, hold file at 30 degrees to bar.
  • Good file handles have markings for file angle.


  • Goals:
    • Remove old fuel.
    • Discover problems that are easier to fox now than later.
    • Clean.
  • Start engine, drain fuel, then close choke when engine begins to die.
  • Must be performed at least once a year regardless of what season the engine is actually used in.
  • Follow other maintenance procedures at this time:
    • Spark plug?
    • Air cleaner?
    • Gearbox lubricants?


  • Question 0: Is it worth it?
  • Question 2: Can I get parts?
    • Most dealers will tell you the parts are no longer available.
    • Most equipment made after 1990 has a great aftermarket.
    • The internet your friend.

Repairing Carburetors

  • Practice on old junk first.
  • Most carburetors are Walbro WA- or WT-series:
    • Gasket and diaphragm kit: K10-WAT
    • Full rebuild kit: K20-WAT
    • NAPA P/N 7-07149
  • Or, ZAMA C3 series:
    • Full rebuild kit (includes gaskets & diaphragms): RB-31
    • NAPA P/N 7-070058


  1. Make sure driven components will not hit anything.
  2. Crank IDLE screw all the way IN.
  3. Turn "L" screw (closer to engine) OUT until engine sputters.
  4. Turn "L" screw IN until RPM is maximized.
  5. Hold throttle open.
  6. Turn "H" screw (farther from engine) OUT until engine begins to die.
  7. Turn "H" screw IN until engine begins to miss.
  8. Turn "H" screw IN an extra 1/8 turn.
  9. Turn IDLE screw OUT until driven components stop.
  10. Turn IDLE screw OUT an extra 1/4 turn.
  • Slide carburetors (no throttle shaft) cannot be adjusted.
  • Some modern butterfly carburetors are not adjustable—check for presence of screw threads on needle base.