Onan Generators are small and compact. For this reason, they are used for recreational vehicle power, and on construction sites where no power is available. Using an internal combustion engine, the carburetor does develop problems from time to time. Onan is aware of these problems and offers some tips for overcoming them.
Fuel Varnishing
Fuel varnishing is a condition that develops when the generator sits for too long. The gasoline dries up, leaving behind a varnish-like glaze on all the components. The varnish binds up the carburetor, not allowing it to work. To prevent this problem, Onan recommends running the generator for at least two hours within a four week time frame. This will keep fresh gasoline in the carburetor, preventing old fuel from drying out.
Carburetor Icing
Carburetor icing happens in the cold weather. The moisture in the gasoline freezes up, not allowing the carburetor to work. The way cure this problem is to heat the generator up to a point above 32 degrees Fahrenheit. Onan recommends running the generator in the "Winter" mode if the temperature dips below 55 degrees Fahrenheit. This allows preheated air flowing over the exhaust to enter the carburetor, preventing icing.
High Altitude Performance Loss
Thinner air at higher altitudes affects carburetor performance. Onan states that at 4,000 feet above sea level, the generator will lose 14 percent of its power. The rule of thumb is that power loss equals 3.5 percent for every 1,000 feet above 500 feet. To compensate for this, the carburetor has to be adjusted for high altitude operating conditions. Onan recommends a qualified service technician do the adjustments.
Surging
Surging is a problem with small generators. Onan stated that the most common cause is a lack of maintenance on the fuel system. To correct this problem, first replace your old gasoline with fresh gasoline. Second, replace the air and fuel filter. Third, run the generator for two hours to flush out all the varnish and deposits in the carburetor. You may want to look inside the fuel tank before filling it with fresh gasoline. If it has dirt or grit on the bottom, clean it.
Tags: fresh gasoline, Onan recommends, this problem, carburetor preventing, degrees Fahrenheit, feet above, Onan recommends running
