Generac MFH500 troubleshooting: 15 fault codes and symptom-cause-remedy entries from the manufacturer's own service documentation.
Generac MFH500 — full specs, parts & maintenance.
| Symptom | Cause | Remedy |
|---|---|---|
| Exhaust smoke is white | Insufficient warm-up time. | Conduct warm-up operation. |
| Engine control system problem | Contact a GMASD. | |
| Faulty injection pump | Contact a GMASD. | |
| Engine running is unstable | Fuel system problem. | |
| Water or air in fuel system | Purge air or remove water. See Removing Water From Fuel. | |
| Exhaust smoke is black | Excessive speed. | Verify engine rpm. Check AVR adjustment. |
| Clogged air cleaner | Clean or change element. | |
| Clogged intercooler | Contact a GMASD. | |
| Engine overheats | No coolant.; Front of radiator is clogged with dust.; Sub tank cap is not tightened.; Fouled coolant. | Add coolant. See Adding Coolant.; Clean with soft brush.; Tighten or replace sub tank cap.; Clean inside of radiator and change coolant. See Adding Coolant. |
| Oil pressure does not rise | Incorrect engine oil viscosity.; Insufficient engine oil level. | Change with oil of correct viscosity. See Draining Fluids—Central Fluid Drain System and Refilling Engine Oil.; Replenish oil. See Refilling Engine Oil. |
| Engine problem | Contact a GMASD. | |
| Engine has no power | Clogged air cleaner.; Clogged pre-fuel filter.; Clogged fuel filter. | Clean element.; See Removing Water From Fuel.; Remove water and change element. See Removing Water From Fuel. |
| Incorrect fuel type | Electromagnetic type fuel pump problem. | |
| Engine cranks but will not start | No fuel. | Verify there is no fuel leakage and replenish. |
| Engine will not crank (electric start) | Discharged battery. | Replace battery. See Battery Installation and Replacement. |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Documented causes: Insufficient warm-up time.. See the table for the matching fixes.
Documented causes: Fuel system problem.. See the table for the matching fixes.
Documented causes: Excessive speed.. See the table for the matching fixes.