Why generators show "engine will not start when cranked": 24 documented causes and brand-specific fixes, compiled across 9 manufacturers.
Faulty ignition
2 brands- Cummins/Onan: Check the ignition system. Repair or replace parts necessary.
- Doosan: Check the ignition system. Repair or replace parts necessary.
Faulty ignition, Lack of fuel or faulty carburetion, Cylinders flooded, Poor fuel, Foil compression, Wrong ignition timing
2 brands- Cummins/Onan: Clean, adjust, or replace breaker points, spark plugs, condenser etc., or retime ignition, Refill the tank. Check the fuel system. Clean, adjusi, or replace parts necessary, Ground spark plug cables, Crank engine with spark plugs moved.
- Onan Electric: Clean, adjust, or replace breaker points, spark plugs, condenser etc., or retime ignition, Refill the tank. Check the fuel system. Clean, adjusi, or replace parts necessary, Ground spark plug cables, Crank engine with spark plugs moved.
Faulty ignition. Lack of fuel or faulty carburetion. Cylinders flooded. Poor fuel. Poor compression.
2 brands- Cummins/Onan: Clean, adjust, or replace points, spark plugs, condenser, etc., or retine ignition. Refill the tank. Check the fuel system. Clean, adjust, or replace parts necessary. Ground spark plug cables. Crank engine with spark plugs removed. Drain. Refill with good fuel. Tighten cylinder heads and spark plugs. Uf still not corrected, grind the valves. Replace piston ings if necessary.
- Prestolite: Clean, adjust, or replace points, spark plugs, condenser, etc., or retine ignition. Refill the tank. Check the fuel system. Clean, adjust, or replace parts necessary. Ground spark plug cables. Crank engine with spark plugs removed. Drain. Refill with good fuel. Tighten cylinder heads and spark plugs. Uf still not corrected, grind the valves. Replace piston ings if necessary.
Faulty ignition. Lack of fuel or faulty carburetion. Cylinders flooded. Poor fuel. Poor compression, Wrong ignition timing.
2 brands- Garretson: Clean, adjust, or replace breaker points, spark plugs, condenser, etc., or retime ignition. Refill the tank. Check the fuel system. Clean, adjust, or replace parts necessary. Ground spark plug cables. Crank engine with spark plugs moved, Drain. Refill with good fuel. Tighten cylinder heads and spark plugs. If still not corrected, grind the valves. Replace pistons if necessary.
- NEC: Clean, adjust, or replace breaker points, spark plugs, condenser, etc., or retime ignition. Refill the tank. Check the fuel system. Clean, adjust, or replace parts necessary. Ground spark plug cables. Crank engine with spark plugs moved, Drain. Refill with good fuel. Tighten cylinder heads and spark plugs. If still not corrected, grind the valves. Replace pistons if necessary.
Faulty ignition. Lack of fuel or faulty carburetion. Clogged fuel screen. Cylinder flooded.
1 brand- Cummins/Onan: Clean, adjust, or replace breaker points, plug, condenser, etc., or retime magneto. Refill the tank. Check the fuel system. Clean. Crank few times with spark plug removed.
Air in fuel system. Lack of fuel or faulty injection caused by dirty fuel. Clogged fuel filter. Poor fuel. Poor compression due to leaky gasket, loose head, worn valves or piston rings. Wrong injection pump timing.
1 brand- Cummins/Onan: Bleed the fuel system. Keep fuel tank filled. Keep fuel clean. Use only recommended fuels. Keep supplies of fuel clean. Replace fuel filter element. Use only recommended grades. Tighten cylinder head. Replace cylinder head gasket if necessary. Grind valves, replace if necessary. Check the injection pump timing.
Faulty ignition, Lack of fuel.or faulty carburetion, Clogged fuel screen, Cylinders flooded, Poor fuel, Poor compression, Wrong timing, Poor choking
1 brand- Cummins/Onan: Clean, adjust, or replace breaker points, plugs, condenser, coil, etc., retime ignition, Refill the tank, Check the fuel system. Clean, adjust or replace parts necessary, Clean, Crank few times with spark plugs removed, Drain, refill with good fuel, Tighten cylinder head and spark plugs, It still not corrected, grind the valves, Replace piston rings, if necessary, Retime ignition, If plant is cold, adjust choke. If plant is warm, pull up on choke arm momentarily, while cranking
Lack of fuel or faulty carburetion. Clogged fuel screen. Cylinders flooded. Poor fuel. Wrong breaker point gap.
1 brand- Cummins/Onan: Refill tank. Check fuel system. Clean, adjust, as necessary.
Defective starting circuit.
1 brand- Cummins/Onan: Repair or replace as necessary.
Air in fuel system Lack of fuel or faulty injection caused by dirty fuel Clogged fuel filter Poor compression Wrong timing Defective glow plugs or leads
1 brand- Cummins/Onan: Bleed the fuel system Refill the tank. Check the fuel system. Clean, adjust, or replace parts necessary Clean strainer (primary) Install new cartridge (secondary) Tighten cylinder head. Replace head gasket. If still not corrected, grind the valves. Replace piston rings
Lack of fuel or faulty carburetion, Clogged fuel screen, Cylinders flooded, Poor fuel, Poor compression
1 brand- Cummins/Onan: Refill tank and check fuel system, Clean, adjust as necessary, Clean, Crank few times with spark plugs removed, Tighten spark plugs
Faulty ignition; Lack of fuel or faulty carburetor; Clogged fuel screen; Cylinder flooded; Poor fuel; Poor compression
1 brand- generatorpartspro: Clean, adjust, or replace parts necessary; Refill the tank; Check the fuel system; Clean; Drain, refill with good fuel; Tighten cylinder head and spark plug
Faulty ignition, Lack of fuel or faulty carburetion, Clogged fuel screen, Cylinder flooded, Poor fuel, Poor compression, Wrong timing
1 brand- Cummins/Onan: Clean, adjust, or replace parts necessary for ignition system, Refill the tank and check fuel system, Clean clogged screen, Crank few times with spark plug removed, Drain and refill with good fuel, Tighten cylinder head and spark plug, If still not corrected, grind valves and replace piston rings if necessary, Reset breaker points or retime magneto
Lack of fuel or faulty catburetion. Clogged fuel screen. Cylinders flooded. Poor fuel.
1 brand- Cummins/Onan: Refill tank. Check fuel system. Clean, adjust, as necessary. Clean. Crank few times with spark plug removed. Drain, fill with fresh fuel.
No fuel, Fuel system restricted, Cylinders flooded, Faulty ignition, Poor compression
1 brand- Cummins/Onan: Replenish., Open., Crank with plugs removed., Service spark plugs and breaker points. Retime if necessary., Repair engine.