Re: No oil problem
You're unsure if the tank was empty? How much oil was in it when you filled it? It only takes 1/2 inch or so to keep the pickup filter covered, so it should be obvious whether it was empty or not.
If it sounded and continues to sound because it was empty and you filled it without priming, it's probably an easy fix (prime, re-set, whatever). The lack of "low oil" warning gives pause though.
If the no oil alarm sounded (and continues) without the tank ever being empty, that's a different set of possibilities. (could explain the no "low oil" warning).
Assuming the first scenario - Is there a priming procedure described in the owner's manual? If you don't have one, you might try to get one - I've found them invaluable when I buy used engines because they usually cover easy and common owner-maintenance stuff like this.
I'm not familiar with Etech procedure, but on the older oil-mixing systems (vro/oms), it's dead easy and just involves disconnecting the oil line at the connection at the engine, pumping the priming bulb until all air is expelled and several ounces of oil flow freely, then reconnecting it. But like I said, I have no direct knowledge of Etech.
I'd also try to figure out why the "low oil" alarm didn't sound if in fact the tank was empty or very low - probably a problem either at the wiring connection from the oil tank, or the float switch inside the oil tank. Should be easy to figure out which.