Technical information
TROUBLE SHOOTING   
30  May 2010 / M-SC3.5 / EN 
PROBLEM  POSSIBLE CAUSE  WHAT TO DO? 
• Loss of compression by wear out or 
damage. 
Repair by Whisper Power. 
Engine runs irregularly  • Unsuitable contaminated fuel. 
• Lack of fuel. 
Fill up with fuel or replace by better quality. 
• Choked fuel filter.  Check fuel filter and fuel lift pump: clean or 
replace if necessary. 
• Disturbances on the electrical system/ 
user side. 
Check if electrical load is fluctuating 
• Faulty fuel lift pump.  Check and repair. 
• Choked air filter. 
• Lack of air. 
Check the air intake. 
• Choked exhaust system, exhaust 
chocked rubber exhaust hose kinked 
Check the exhaust hose. 
• Air in the fuel pipes.  Bleed air from fuel system (refer to 
maintenance section). 
• Blocked injector.  Have the injector tested and cleaned if 
necessary. 
• Wrong valve clearance.  Adjust valve clearance. 
  • Temporarily hunting (this will disappear 
when engine has run in). 
Engine speed drops  • Too much oil.  Drain oil to proper level. 
• Lack of fuel.  Check fuel supply system: fuel pump and filter. 
• Lack of intake air.  Check air intake. 
• Choked exhaust system, exhaust 
blocked, rubber exhaust hose kinked. 
Check exhaust system. 
• Generator overloaded  Reduce the electrical load (switch off some 
consumers). 
• Generator over energised.  Check that the proper capacitor type is 
installed and that it is connected correctly. 
• Defective generator (windings, 
bearings or other) 
Generator must be sent to manufacturer for 
repair of damaged bearing or winding. 
• Damaged engine  Repair by Whisper Power. 
Engine does not stop on 
command 
• Loss of control.  Faulty Local Control Panel. Stop the engine 
manually by the stop handle. 
Check wire connections to stop solenoid. 
Check solenoid valve function. Replace if 
necessary. 
Engine exhaust smokes  • Faint blue smoke - generally the result 
of light load 
Increase load. 
  • Heavy blue smoke - caused by 
lubricating oil. Overfull oil sump or worn 
cylinder bore, stuck broken or worn 
rings. 
Check the oil level. 
Check the compression. 
  • Black smoke - incomplete combustion 
caused by: overload, choked air filter, 
inlet temperature too high, unsuitable 
fuel or water in fuel. 
Check the fuel . 
Check for overload. 










