WEN Gen & Schneider AGS

Running it on propane might work with an AGS since that doesn't need a choke.  Your generator doesn't have an automatic choke shown in it's wiring diagram (meaning it wouldn't be able to be started on gasoline remotely).   

From what I've seen there isn't a standard AGS connection available for the Wen but that doesn't mean that it can't be hooked up. Someone who knows what they are doing could do it fairly easily.  Usually only the larger gensets (i.e. those over 10 kW) have standard AGS connection terminals.  There is really a missing market niche for a 5 kW 120/240V AGS inverter generator that runs on propane.

You might be able to get help from the people in the thread at the link below who have a similar Wen generator hooked up to an AGS remote start module.   The hookup can be fairly simple to figure out if you take the time to look at the manuals and the wiring diagrams to see what's needed.   You might read the AGS manuals for the Schneider, Magnum and Atkinson generator auto starts as they all have good explanations, each covering most of what you need to know. After gleaning info from reading them all you will probably understand enough to figure it all out.

https://diysolarforum.com/threads/looking-for-a-propane-inverter-generator-with-auto-gen-start-interface.71216/

That said, you'll need to get it right for safety - so probably best to hire someone who knows this stuff!!

Your wiring diagram only shows the interior of the generator and not the generator switch section but it looks like a simple two wire start would work, the AGS would need to monitor generator output voltage to confirm that a start has occurred and shut off cranking in some defined time period if not.   

This setup while simple, does not have the numerous safety over-rides that a proper remote start designed generator would have.

I've marked up typical connections for a "two wire" type of start wiring scheme.  You'll find more info in the manual for the Schneider AGS.