Coupler on 2046W tender not holding

[emptyhook53]

Just had my tender and engine serviced and now the coupler will not hold--cars come uncoupled and the engine and tender head off to where ever.  I looked at the coupler and it appears the plate holding the pin is loose.  I looked for a screw to tighten but can't see anyplace for an adjustment to be made.  It is the truck with the pickup for the whistle.  Any suggestions would be most appreciated.

Jerry

[ben10ben]

Take a pair of needle-nose pliers and carefully bend up the arm to which the pin is attached. Just a little bit makes a big difference. This puts more tension on the pin, which will help prevent it from pulling loose.

I've had a few that I haven't been able to fix. In those cases, I've used a plastic zip-tie around the coupler and pin assembly to hold it closed.

[lionelsoni]

Before you try bending the armature, check the spring.  It is a transverse strip of (I think) bronze, connected through the baseplate to the armature by a rivet.  I think yours, or one similar, is shown in this pdf:

http://pictures.olsenstoy.com/cd/mistrk/mistrk8.pdf

If the spring is just bent, you may be able to straighten it without disassembling.  I would try holding it up with the end of a bent paper clip close to the rivet, then pressing down just a little bit farther from the rivet with a screwdriver tip.  (This works with e-unit springs--I haven't tried it with a coupler spring.)