The Onan A042P619 is a genuine Cummins Onan factory replacement carburetor designed specifically for the popular MicroQuiet KY Series 4000-watt RV generators. This carburetor is the solution when cleaning, adjusting, or rebuilding your old carburetor just won't cut it anymore.Genuine OEMKY SeriesGaskets Included
The MicroQuiet 4000 is one of the most widely used RV generators on the road, found in travel trailers, 5th wheels, and motorhomes from virtually every manufacturer. Over time, carburetor issues are the #1 cause of generator problems – and replacing the carburetor with this genuine Onan unit is often the quickest path back to reliable power.
Modern gasoline (especially ethanol blends) creates varnish deposits that accumulate in the tiny passages of your carburetor over time. Each time fuel sits, another layer builds up – like paint – until fuel flow is restricted. While cleaning can help temporarily, a new carburetor ensures: • All passages are clear – no hidden varnish buildup • New float and needle valve – proper fuel metering • Factory calibration – correct air/fuel mixture • Fresh gaskets – no air leaks that cause lean running
While aftermarket carburetors are available for $35-50, many RVers report issues with quality, float adjustment, and longevity. The genuine Onan carburetor is factory-calibrated, built to OEM specifications, and includes proper gaskets. For a generator that powers your air conditioning, refrigerator, and other essentials, genuine quality matters. Note: Cummins Onan advises that for KY Series generators Spec J and beyond, if the fuel solenoid fails, the complete carburetor must be replaced – the solenoid is not available separately.
This carburetor fits KY Series (non-EVAP) generators, Spec A through P. Check your generator's model/spec plate for compatibility. The spec letter is the last letter of your model number (e.g., 4KYFA26100K = Spec K). NOT for EVAP-equipped models – those require a different carburetor configuration. Tip: If unsure, call Cummins Onan at (800) 888-6626 with your model and serial number.
Once you've installed your new carburetor, keep it running well:
The Onan MicroQuiet KY Series is the gold standard for RV generators. Known for its quiet operation (as low as 52 dB), compact size, and reliable power output, it's been factory-installed in RVs since the late 1990s. The 4000-watt output is perfect for running a 13,500 BTU air conditioner plus other appliances. With proper maintenance, these generators routinely achieve 5,000+ hours of service life.
Parts Manual: → Onan KY (Spec A-R) / KYD (Spec A-C) Parts Manual available at Cummins
Cummins Onan Support: → (800) 888-6626 → shop.cummins.com
Troubleshooting: → Flight Systems RV Generator Troubleshooting Guide (flightsystems.com)
Check your generator's model plate for exact model and spec letter.
Cummins Onan Part of Cummins Inc. (800) 888-6626 cummins.com/onan