Re: 91 force 50hp.
1. Yes you can run it without the thermostat, however, the motor was designed to run at a specific temperature range. If the motor doesn't reach proper temperature, then performance and efficiency suffers.
2. I have a 125 HP Force so I'm not sure I have the answer for your particular motor. On mine, at around idle speed and below 2000 RPM's, water and exhaust kind of spits out of the exhaust/water holes that are located about halfway up the lower unit. Once I get going, say above 4000 RPM's, then I see solid streams of water coming out.