First since no one has said it yet, ditch the cheap hose and get some good hose that won’t kink.
Your temperature sensor is there for a reason, to alert you to high temps. While running it that long without water is not a good thing, it sounds like you took immediate action as soon as you got the alarm, so chances are no damage.
I think Jeff
@Cobra Jet Steering LLC steering is right, you don’t have to worry that you got any water in the cylinders as you took immediate action once you figured out what was going on, and that was only 7 seconds, with a kinked hose.
I’m assuming that you had unkinked the hose and got water flowing before you shut it off properly and rapped the engine three times to remove water from the water lock?
From now on I bet you will stand there and watch your pilot outlets to make sure you have water running through the engine, and it does take a bit once you turn the water on. This is in the manual, even when I start my boat on the water I check to make sure water is coming out of the pilot outlets.
That check engine see the dealer thing happened to me one time when I sucked up some grass or something and the motor got hot while I was on the water. Once I cleared the debris I drove around the lake a few times, and during that time I shut everything down, turned off the batteries then back on and drove around some more and that alarm and check engine see your dealer was locked in. I docked the boat thinking I was going to have to make the journey to go see a dealer, feeling kinda the same you do, I just messed up one of my brand new engines!!!! After I got the trailer in the water I started the boat, the alarms were gone. That was probably 245 hours ago when I had 5 hours on the engines and no problems since. The rule of thumb is cycling the batteries on and off 5 times will clear the problem, perhaps a few more times. You can try this by just turning the batteries on, let it sit for a few minutes, then turn them off and let it sit for a few minutes, etc…
As far as the smoke goes, it was probably just some oil or other corrosion inhibitor that was burning off from the inside of the exhaust manifold or the water lock muffler.
From where I sit, what’s done is done, it totally sucks but you cannot change it, and taking it to the dealer isn’t going to change that. If you planned on a maiden voyage this weekend, then go and do it. Run your break in procedure as detailed in the manual and go have fun. I know you are super worried but if the engines are not running rough as Jeff stated then probably nothing damaged except your ego.
P.S.
If you are not mechanically inclined then stay away from the spark plugs.
