Re: Orca system closed cooling operation
While its true that you don't have to worry about the thermostat opening on a closed cooling engine, the issue with using antifreeze that way is if the impeller can suck it in fast enough so that the impeller does not get burned up and the engine does not overheat. Sometimes with an engine mounted impeller unless you pressurize the AF flow with a bilge pump or similar the impeller can't get primed because of the distance from the lower unit intakes and the impeller. If it were me I'd flush the engine, change the motor oil and filter, run it again to make sure the filter does not leak, fog it and then drain the heat exchanger and manifolds. I'd then manually fill the raw water side of the exchanger with -100 AF and the manifolds as well. Simple, fool proof, no burned impeller no overheated engine.
If you have an Alpha drive it may work as long as the muffs fit really tightly since the Alpha impeller is right in the lower unit. But the manual drain and back fill method is the best way.
I honestly do not understand the fascination people have with these winterizing kits, they are a short cut that can wind up being a real headache if you wind up with a burned impeller, an overheated engine and still have to get the boat winterized. Just drain it. You really don't have to even add AF for freeze protection if you drain it right, its really for corrosion protection because it keeps air out and adds corrosion inhibitors.