I hate to say it but I seem to be getting a lot of conflicting information in this thread so I am going to continue to work with Westinghouse on the issue and if I come to a definitive conclusion I will post it here. Thanks to everyone for chiming in though.
Here is what the post says...not contradictory; just not all put to gether in a single post. Remove the genset regulator, run off the quick connect, always close the valve when it's off, and bleed the line if it's still rough. Worth hearing back from Westinghouse, but the advice here wasn't actually contradictory.
Lots of us here in Florida have dual fuel, whole house generators, including me (also a Westinghouse), and I know what is happening with your unit when you connect the LP. The following four points are important to understand.
First, there is only one carburetor that manages both fuel types.
Second, with the engine running, there is always vacuum; the vacuum opens the demand regulator on the LP...it does not care if the sector switch is on gas or LP.
Third, the switch between LP gasoline is not a positive disconnect between LP and Gasoline, it changes air fuel ratios for either gasoline or LP, nothing more.
Fourth; there are two positive disconnects...the petcock to shut off gasoline on the generator and the valve on your LP tank; the selector switch position is irrelevant to the available disconnects. If you read your westinghouse manual, it will tell you that when you switch from either fuel source you must positively disconnect the fuel you are not using. So running on gas, disconnect LP(valve at QC or valve at tank, or completely disconnect); LP, disconnect gasoline (petcock).
Without turning of the gasoline petcock, and opening the LP, you "flooded" the engine with a mixture of LP and gasoline. That is why it died. Go to the manual and find the troubleshooting page. Look for engine stalling on propane. It tells you right there that when this happens, stalling, you need to close the petcock and remove the LP supply, purge the carb of gas by starting and running until it dies, then reattach LP, switch to LP, and start. It will run rough for a few seconds, maybe die, but it will start right back up.
If you want to keep the LP regulator on the generator you can retrofit one of your tanks with this and run the quick connect line to this.
https://www.adventurerv.net/acme-extendastay-adapter-p-5105.html
On Westinghouse, incredible customer service. Right after Hurricane Ian, my genny threw a rod with about 15 hours on the motor. I called them, told them what happened, and they asked for a picture. Literally 28 hours later, a brand new generator was in my driveway and the other hauled away.
