Why generators show "engine will not start": 193 documented causes and brand-specific fixes, compiled across 18 manufacturers.
Spark plug faulty, fouled, or improperly gapped
3 brands- Cummins/Onan: Gap or replace the spark plug. Reinstall
- Echo: Replace spark plug
- Honda: Gap or replace spark plug (see page 52); Gap or replace spark plug (see page 68)
Stale gasoline or water in gasoline
3 brands- Caterpillar: Drain entire system and refill with fresh fuel
- DuroMax: Drain entire system and refill with fresh fuel
- Echo: Drain entire system and refill with fresh fuel
Fouled fuel filter
3 brandsAir in the fuel injection system
3 brandsWater / contaminants in the fuel
3 brandsPreheating insufficient
3 brandsStarter element defective / not connected
3 brandsFault in the GAC unit (generating set engines)
3 brandsFuel Tank empty
2 brands- Echo: Fill tank ensuring you do not overfill
- John Deere: Fill tank per instructions in this manual
Engine switch is off
2 brands- Honda: Turn the engine switch on
- John Deere: Turn engine switch to the ON position
Out of fuel
2 brands- Cummins/Onan: Refuel
- Honda: Refuel (see page 19); Refuel (see page 42)
Dirty air filter
2 brands- Caterpillar: Clean the air filter.
- Cummins/Onan: Clean the air filter
Spark plug wet with fuel (flooded engine)
2 brands- Cummins/Onan: Wait five minutes. Turn battery switch to the OFF position. Pull recoil handle rapidly several times. If the generator does not start, remove spark plug and dry
- Honda: Dry and reinstall spark plug
Slow cranking speed
2 brands- Allis-Chalmers: Specific gravity of battery too low. Charge battery. Starter not delivering maximum torque. Repair or replace defective parts. Use cold weather starting aids if applicable
- Doosan: Recharge battery