Replacement Generator for a Cummins Onan 4KY-26100R

Updated 09/08/2026 | Published 09/02/2026

Products Featured in This Question

Onan Generator - QG 4000i DF Onboard RV Generator - 4,000 Watts - Gas or Propane

$4194.00

Question:

This is replacing a Cummins Onan 4KY-26100R Spec R, serial B220040930, in a 2022 Gulf Stream Conquest 6280D Ford Class C. Please confirm CM66GR is the correct replacement and identify any required EVAP, exhaust or installation components. Attached photo is from the unit that is installed on my RV.

asked by: John

Cummins Onan 4KY-26100R
(click to enlarge)

Expert Reply:

Hey John, thanks for the picture! The Onan Generator - QG 4000i DF Onboard RV Generator item # CM66GR is a comparable replacement for your Cummins Onan 4KY-26100R. They have the same physical footprint, weight, 4,000 watt power output, and electrical connections.

The exhaust ports are in identical locations on your Cummins Onan 4KY-26100R and the Onan Generator - QG 4000i DF Onboard RV Generator item # CM66GR as well so you won't have to worry about rerouting it. You will need to reroute the fuel line though.

The EVAP system has an extra fuel vapor port on the Onan Generator item # CM66GR. Since the Onan 4KY-26100R doesn't have an EVAP system, you will need to cap or plug this additional vapor port on the new generator during installation to prevent fuel vapor leaks.

What appliances do you typically power off of the generator? Feel free to answer this and throw in any other questions you have, where it says Add Comment.

expert reply by: Jerred H