Frank your comment didn't show up in the discussions on the 40/43 site. It's simply a comment on your page. Not sure if others will see it. For what it's worth I don't have the problem on our boat. There are two pieces of hardware holding the track in place, one on either end of the track. Look under the end caps for them. You should be able to tighten them with a hex key. There's a small flat square that fits inside the boom that the bolt screws into. I'd also check the car that rides on the track as they can lose the bearings allowing the car to become loose fitting on the track. Although if you're missed enough bearings it usually results in the car binding.
How is everything with you, I picked interest on you after going through your short profile and deemed it necessary to write you immediately. I have something very vital to disclose to you, but I found it difficult to express myself here, since it's a public site.Could you please get back to me on:( firstname.lastname@example.org ) for the full details.