Propane torches won't generate enough localize heat as the rest of the engine will heat sink away too heat. Don't know about the MAP version as to if they are hotter but I do know that propane torches won't be unless boosted by oxygen. I have tried those homeowner style systems too many times and gave up and brought a regular Ox/Ace setup.
From the pictures it looks like a bearing separator setup would better at getting a good grip on the adapter. If it was in my shop I would install the separator ( may need a separate bolt in the crank to push against), tighten the center puller bolt with an impact until it just stops under tension, then apply heat with an ox/ace torch. Testing as I as heat by tightening the puller bolt a little until the adapter starts moving, that way you only apply enough to loosen the adapter.
Now this is just I would do here but it is what found that works reliably here but of we don't have Victas here.
