Gen start

[Neal]

Yeah, I think that may be the difference is the auto prime.

 

[Buly]

JJ, Your Canyon Star Genny starts right away because it is a gas engine (I think). Gas engine does not need preheat. Fuel pump is activated on together with the starter.
Diesel needs help with the initial start (Glow Plug). That's why it takes few seconds longer than a gas engine.
Diesels have two fuel pumps. The first one is a lift pump that brings fuel to the engine driven high pressure (26,000 - 30,000 psi) pump that feeds the injectors thru steel fuel lines.

 

[Joe Hogan]

According to the Cummings - Onan Generator user manual :

3 | RV GENERATOR OPERATION STARTING AND STOPPING PROCEDURES
Your Cummins generator can be started (except RV QD 3200) and stopped from the integral control panel on the generator, or from the optional remote control panel inside the vehicle if your RV is so equipped. It is a good practice, before starting the generator, to turn off air conditioners and large electrical loads.

If the unit has not been started in the last several hours, prime by holding the stop button on the remote start panel or the control on the generator itself.

NOTE: Prime is available for all current production models, but may not be available on some Legacy products. If you have an automatic generator start system the delay is built into the automatic transfer switch.

To start:
n Press and hold START at the interior control panel or outside at the set.
n Quiet Diesel: When you press START, the control verifies several parameters, including temperature. Glow plug burn and fuel pump prime happen prior to the starter engaging.

On a cold morning, this ‘Prime’ could take up to 30 seconds before you hear the starter engage. This is normal.

n Don't over-crank with no start—crank no longer than 20 seconds; allow the starter to cool for at least two minutes between attempts.
n Allow generator to run for 30 seconds prior to applying large loads. In many cases the RV’s automatic transfer switch has this delay built in.

To stop: Press the STOP button at the control panel or at the set.

https://mart.cummins.com/imagelibrary/data/assetfiles/0056746.pdf