I am not real familiar with a 250 but I do know that a Ford starter should fit into a circle of the plate and the use of shims or washers will only move the starter gear in and out in depth which is set by design. To add shims will move the gear away and not allow the starter to fit into its slot and the starter will be misaligned causing flywheel damage and starter nose damage.
I am thinking there may be a misalignment issue even without the use of a shim. .. Maybe the starter is cocked when tightened? You might check the starter is seating.
Everything appears to be aligned and 3 different mechanics including myself have replaced these things. Also you usually get some noise etc when starter starts to go or flywheel teeth missing etc. These starters have been perfectly quiet and smooth right up until she starts it....hears metal particles flying (bearings breaking) then its out. Have talked with mechanic after mechanic.....all stumped.
Engine starts good running wise? No need to crank excessively? Does anything seem like it was changed or anything? Like bell housing, trans, engine?
Cold natured in the morning. Starts pretty normal. Engine is tired and needs rebuilt or replaced but runs good. Has that bottom end rattle. Been that way since we bought it 4 years ago. No changes to trans.
lol.. Bottom end rattle.. I'm picturing the crank waubling at the flywheel and pressing on the starter haha.. I'm stumped also.
LOL.....that was my exact thought too but wasn't sure if that was even possible? Main bearings worn, crank moving, that would cause flywheel movement. That even possible? It went through my head last night and today. lol
Probably need to go ahead and rebuild the engine & replace the flexplate. Many years ago, I went through 5 starters in my Maverick (but it was never the bearings). I think I was just getting poorly re-manufactured starters, because the last one I got has been working great for the past 20 years.
I'm going have to agree with you on that one. Time for an engine and forget about these starters. Reman stuff these days...I don't know. Never seemed to have any problems years ago.