Sunrise, this isn't going to be much help, but I just want to respond to let you know that your MTH presidential is not the only one with problems.
I bought one brand new from Western Depot last Spring (Mayflower edition - same engine, just shinier). It arrived defective, loose rods, reversing unit cycled continually, useless. Western Depot was great, got me a repair order number with MTH, paid label, so I sent it off. MTH had it for 6 months, and the people there actually literally laughed at me when I called up to ask how it was coming. They finally shipped it back to me still not working, plus missing the brass eagle and flags.
With Western Depot's intervention, Jeff Strank, head of service at MTH, has become involved and emailed me another prepaid label, and two days ago I sent it back to them again, after getting his assurance that it would go better this time.
MTH's "explanation" has been that they are waiting for parts. In view of the fact that I can buy a new reversing unit on eBay for $20 and have it here tomorrow, I find this a little thin, but don't get me started. Suffice to say that there seems to be an issue with these traditional-powered MTH Flyer Presidential-type locos.
I am capable of some repair on these traditional mechanisms, they are after all fairly simple. I did look at the this mechanism myself and decided it wasn't for me. The Ives mechanism makes sense to me, this one does not. But I would imagine there must be a lot of traditional train repair gurus out there for whom this would be a piece of cake. If Western Depot hadn't gotten Mr. Strank's attention for me, that is the route I would have gone, and may still go if this doesn't work out.
Good luck.