Failure to Start
The failure to start or rough operation is due to a multitude of reasons. One, fuel problems. When portable generators are stored and not used for a while the fuel degrades. If there is stale fuel, drain the fuel and replace it. Also, check to make sure the fuel shutoff valve is not engaged. If it is still not starting, the stale fuel might’ve clogged the fuel lines, engine, or fuel pump. If this is the case then the generator needs to be brought into a repair shop. Another cause of a generators failure to start is oil problems. Low oil levels will not only cause failure to start, but it can cause permanent damage. Low oil is often detected by a sensor, so there is no reason why low oil should be missed. However, if the sensor goes off and the oil is not low, the sensor is faulty and should be replaced.
Sputters and Stalls
If a portable generator sputters and stalls it may have clogged air filters. If the generator is being used in a dusty, dirty area make sure to check the air filters regularly. Clogged filters lead to inefficiencies because it causes an improper gas to air ratio. It is important to note that generators should never be run without an air filter because it will cause permanent damage. Another reason for a stalling generator is fouled spark plugs. Over time there is an accumulation of sludge or dark carbon. Before changing the spark plug make sure the electricity is running to the plug. If the electricity is running to the plug then changing the spark plug will solve the problem. It is important to note also that a fouled spark plug can be reasoning for a generator not starting.
No Power/ No Voltage
This can be caused by the loss of residual magnetism. If the generator has not been used in awhile, runs too long without a load or the generator runs too long with a load that is turned off it can be expected that there will be a loss of residual magnetism. To build the residual magnetism backup connect the generator to a 12-volt battery, or plug a drill in and use the motion of the drill to generate electricity, which in turn will create residual magnetism.