Damn, I hate those Catch 22 incidents: you can't perform oil change
maintenance cause you can't get the cap off

Like you said, the whole thing just turns, which Sears acknowledged is
a problem...'yah, just grip the tube with vice-grips, and yank like
hell on the cap, that'll do it'

I'm still looking for a online manual (original lost in a
move)..suspect it will say just 1 year warranty and 'suggests' the oil
needs to be changed each season regardless of how many time the blower
is used.

Service will probably just tap out the hole in the engine housing and
put a bigger size tube in...something I may consider doing myself after
I speak with them

Thanks all for the feedback