GP-9 Intermittent Movement

Don, the make, model, and operating environment would be useful to provide a somewhat intelligent answer.

Obviously, if it's running poorly, lube and cleaning wheels/pickups is on the top of the list.

Lionel #11864 NYC GP_9

That's important information!  I'd for sure do some maintenance on the motor.  Pop the brush plate, clean the commutator and brushes, and also make sure the brushes don't need replacement, they should be at least 1/4" long and the springs should keep them firmly in contact with the commutator when it's assembled.

thanks

But, if it truly NOS he shouldn't have to do that (although the factory grease might have become a bit thick and the oil may no longer where it should be).  I've bought two NOS engines from that same era, and they ran fine out of the box.  Or is he saying that he bought it NOS and he's run it for a bit?

Maybe, but if it's not running well, and lubing and cleaning the wheels/pickups don't fix it, I'd do some maintenance on the motor, including cleaning and lubing the axles.

Obviously, this is all being diagnosed in ASCII, pretty hard to know exactly what the symptoms are without actually seeing and hearing it.

@Don Beck posted:

So I bought this NOS and has not been run in a while I suspect, Im wondering if its not lubed enough (haven't done that yet) or something more serious. The track it runs on is fine, everything else runs OK.  Any suggestions before I start lubing her up?

My first thought - if it’s NOS, why would you “suspect” it “has not been run in a while”. If it is truly NOS, it hasn’t been run, unless by you.
Secondly, if it’s a recent NOS aquistion, why not get the dealer (ebay seller?) involved, if it was represented to be operational at time of sale.

I bought several NOS and NIB items, some from eBay, some from an auction house.  They were all unused as far as I can tell except for one item I bought on eBay from a low volume seller.  It was an unpowered Santa Fe B Warbonnet unit at a really good price.  Looking at the wheels, it had obviously been run some, pretty dirty.  However, the shell was perfect, everything else looked great, and as I said the price was okay, so I didn't make an issue.

So, if the engine is acting up, I suspect it might not be NOS.

Clean the wheels and pickups good with alcohol. Check the truck screws are tight.

All good advice and make sure there's nothing binding in the drivetrain and that nothing's rubbing the wheels, like a brake shoe or side frame.