It's almost certainly the gauges in the panel.

The engine gauges tend to be engine-type specific. If you've successfully changed the engine type in the aircrft.cfg (you won't need to access the .air file under normal circumstances), then some of the gauges, which can include starter switches, simply won't work.

You'd need to install a prop panel to fly it.

I believe you can eliminate any panel problems by hitting  Ctrl+E

That turns everything on and starts the engines redardless of any gauges or switches you have (or don't)

You can use a copy of just about any .air file (almost) to get the engines running... All the meaningful parameters  (that you're likey to notice or even care about) are defined or redefined by the aircraft.cfg file.

Okay, I've tracked down the problem--its the .air file.

The aircraft wouldn't work even when I changed all the electrical systems, so I took the process a step further and copied the .air file from the Kingair to the V22.  That got me past the engine problem (they work now) but it gave me another issue.

The engines on the V22 rotate to vertical by the use of the flaps and spoilers.  The problem is that when I switched the .air files, it also overwrote the ability for the engines to register the rotation.  They still move on the model, but there is no upward lift.  I don't know of any way to fix this, so I'm thinking of abandoning the project until I can find a good resource for editing the .air files themselves, but I would still appreciate any suggestions.

Anyone?