Generator Maintenance Schedule

A generator that fails to start during a power emergency is worse than not having one — it creates a false sense of security. Generators require regular maintenance to remain reliable, and the most common generator failures (stale fuel, dead battery, fouled spark plug) are entirely preventable with a simple maintenance routine.

The Most Common Generator Failure: Stale Fuel

The majority of generator failures when needed are caused by stale fuel that has gummed up the carburettor. Petrol (gasoline) begins degrading in as little as 30 days and leaves varnish deposits in the fuel system that prevent starting.

Prevention:

1. Use fuel stabiliser in any stored fuel
2. Run the generator monthly (at load) to cycle fresh fuel through the system
3. If storing the generator long-term, drain the fuel or use stabilised fuel only

Maintenance Schedule Overview

Task	Frequency
Test run (10–15 min at load)	Monthly
Check oil level	Before each use; monthly
Check air filter	Monthly; replace annually or as needed
Check spark plug	Every 6 months; replace annually
Change engine oil	Every 50–100 operating hours (see spec)
Inspect fuel lines and connections	Annually
Check battery (electric start models)	Monthly; replace every 2–3 years
Full professional service	Annually or every 100 hours

Monthly Test Run

Why: Keeps the engine lubricated, cycles fuel, confirms the unit starts and runs, and identifies problems before an emergency.

How:

1. Check oil level — add if needed (see spec for correct grade)
2. Check fuel level — add stabilised fuel if running low
3. Start the generator — electric start or pull start
4. Allow to warm up for 2–3 minutes at no load
5. Connect a real load — a lamp, fan, or other device that draws at least 50% of rated capacity
6. Run at load for 10–15 minutes
7. Disconnect load; allow to cool under no load for 2 minutes
8. Shut down normally

Record the run date — this creates a maintenance log that helps identify problems before they become failures.

Oil Changes

Engine oil degrades with heat and use. Running a generator with degraded or low oil causes engine damage.

Check before every use:

1. Remove the dipstick; wipe clean; reinsert fully; withdraw to check level
2. Oil should be between the min and max marks
3. Oil should be clean to slightly amber — dark brown or black oil needs changing

Oil change procedure:

1. Run generator for a few minutes to warm oil (warm oil drains better)
2. Turn off and allow to cool slightly — hot oil causes burns
3. Place a drain pan; remove the drain plug or tip the generator (check manual)
4. Allow oil to drain completely
5. Replace drain plug or restore upright position
6. Add fresh oil of the specified grade (check manual — typically SAE 10W-30)
7. Check level with dipstick; do not overfill
8. Dispose of old oil at a recycling facility

Change interval: Every 50–100 operating hours, or annually at minimum regardless of hours.

Air Filter

A dirty air filter restricts airflow, reduces power output, and increases fuel consumption:

1. Remove the air filter cover
2. Inspect the foam or paper element — grey or black means it needs attention
3. Foam filters: wash with soapy water; rinse; allow to dry completely; apply a light coating of oil before reinstalling
4. Paper filters: tap gently to dislodge loose dirt; replace if heavily soiled
5. Replace the filter element annually

Spark Plug

A fouled or worn spark plug causes hard starting, rough running, and poor efficiency:

1. Remove the spark plug wire; use a spark plug socket to remove the plug
2. Inspect the electrode — moderate grey colour is normal; black sooty deposit suggests rich fuel or oil fouling
3. Check the gap with a feeler gauge — spec is typically 0.7–0.8mm; adjust if needed by gently bending the electrode
4. Replace the plug annually or if the electrode is worn or heavily fouled
5. Reinstall finger-tight + 1/4 turn more with the socket (do not overtighten)

Battery (Electric Start Models)

Electric start generators have a battery that depletes during storage:

1. Check battery voltage monthly — should read 12.4–12.7V when fully charged
2. Use a battery tender or trickle charger to maintain charge during storage
3. Replace the battery every 2–3 years or when it no longer holds charge

Pre-Emergency Checklist

Before a forecast event (hurricane season, winter, etc.):

• Run and load test ✓
• Oil level checked ✓
• Fuel topped up with stabiliser ✓
• Air filter inspected ✓
• Extension cords available and tested ✓
• Fuel storage topped up ✓

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Quick Reference

Task	When	Time Required
Test run at load	Monthly	20 minutes
Check oil	Before each use	2 minutes
Change oil	Every 50–100 hrs or annually	30 minutes
Inspect/clean air filter	Monthly	10 minutes
Replace air filter	Annually	5 minutes
Inspect/replace spark plug	Annually	15 minutes
Battery check (electric start)	Monthly	2 minutes
Full service	Annually	1–2 hours