Generac RV generators, the kind you build into a sound-isolated, heat-resistant compartment of the RV, have safety sensors that prevent the unit from running if a condition exists that will do damage to the generator. The most common complaint with a Generac that won't stay running is the oil level sensor. This sensor shuts down the engine at low oil level. The engine uses a small amount of oil as a matter of course; keeping the oil level up is the simple fix. Other causes include the high temperature sensor, spark plug wear and dirty carburetors.
Find the oil filler plug at the bottom of the generator assembly. It will have a small oil can symbol on it or have a flat knob you can pinch between thumb and forefinger. The filler plug is threaded and has a black O-ring just above the threaded portion for a good seal. A flat protrusion with fill markings dips down into the oil pan from the plug. Check the oil level with the generator off. If it is low, fill it to the maximum and try to start the generator. If it stays running, you need look no further.
Add a container of injector/carburetor cleaner to the fuel supply if the oil level is fine. If the generator is installed in a motor home, the RV's main gas tank usually feeds the generator; add the cleaner there. Drive the motor home until the gas tank is almost empty and add another container of cleaner with a full tank. Purge the gas supply line to the generator by draining about a quart and reconnecting the line. Crank the generator; if it stays running, the problem was contaminated fuel.
Remove the spark plug lead and take out the spark plug. If the generator still will not stay running, especially under load, you probably have a fouled plug. Inspect the plug electrodes for oil or carbon buildup and use a small file to take off the carbon. Reset the gap to manufacturer's specs using a gap gauge.
Contact Generac for your nearest authorized service shop if all else fails.
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