250 hrs is WAY too much on an impeller. You're lucky it's still going.
There was a thread I posted on not too far down on this same thing, searchy searchy.
It helps a lot to spray Simple Green or soap into the impeller and bump the starter to swirl it around. Not sure why the mechanic suggested a remote starter - I would definitely NOT bump the starter with tools or fingers in the pump.
Depending on where the clearance you have around it is, you can get a puller from skidim, or use vise grips, two screwdrivers, needlenose pliers, or some combination.