I know little about the 850 but I agree that it sounds like the starter. My old 1979 Olds Delta 88 with a 350 Olds engine, son's 940, and then there was the frantic co-workers Toyota whatever car in the parking lot. Solenoid stuck, dried out lubrication, rubber bushing in there somewhere that swells when hot...

This may or may not work, all three cars were restarted with a "tap" or 2 with a metal tool such as a tire iron or what ever can reach.

BTW, son was happy and used the tap method for a month or more until he, at his leisure, could get the car over to my house.

Tom