Help Finding Lionel Can Motor Thrust Washer

Check your motor mount screws also.

Yes Bill, that's the one.  You are GOOOD!!!.....as always 

I  checked the 2 small motor mount screws and they are snug. 

I am starting to wonder if the thrust washer is really the culprit.  The gear set keeps binding up.  Besides broken teeth and lack of lube what else should I be looking for? 

Is it normal for some idler gear to be kind of non-concentric?  The idlers near the rubber tire wheels seem like they have lots of slop (both front truck and back) on their mount.  Is that normal?

It could be to much slop in the gears, something in the gear teeth. Also make sure the bearings flats are seated in the right posistion.

Bill

I see the importance of setting the bearing flats correctly.  That is sound advice.  With the motor out and the worm gear shaft out I checked out the running gear.  The rear and mid axle rotate fine including idler.  The front axle and idler spin fine.  When I drop in the worm gear shaft things get a bit more resistance.  Then I mount the motor and I can spin everything fine with the flywheel.  Next it goes on the track and after about 1 foot forward the rear truck locks up.  It will go in reverse but then keeps locking up going forward.  I grab the flywheel and it is bound up.    

Can you apply power with jumpers and watch the motor and gears.

Bill

I have jumpers.  I just have to arrange something to hold the engine up.  I will do that in the morning.  I will report my results.

The worm gear forces that shaft the worm wheel is on one way or the other,depending on the direction the locomotive is going.  Binding up in the forwar direction would be expected, since that is the direction the locomotive probably operates most frequently.  Check the shaft that the worm wheel is on to see how thrust is taken in the direction the shaft would be forced when going forward.  Wear in that thrust bearing may be your problem.  

That makes a lot of mechanical sense David. Besides the shaft "journal" bearings there is also a metal washer and a nylon washer on that shaft.  I best make sure that they are in the proper location to withstand any axial shaft thrust. 

As for the motor worm thrust bearing, there is plenty of clearance between the end of the motor worm gear and the bore of the thrust bearing.  Feels like about 1/16" and I will try and measure.

I see the wisdom of your suggestion Bill.  I did the test that you recommend and here are the results.

The front motor purrs like a kitten, smooth as can be in both directions.  The rear motor, stalls and studders below 1/4 throttle.  Anything above and it runs in step with the front motor.  Gear sets sound good.  I checked the wire connections for the motor leads under the wire nuts (blue and yellow wires) and nothing abnormal.  Both motors are wired in parallel and should be moving the same, all the time.

I will separate the motor from the truck and repeat the test to confirm that I don't have low speed gear set drag.  If the motor continues to stall/studder when removed then I'm thinking of either a high resistance connection/wire or a internal motor problem.

Testing the motor is the next step.

Bill

I removed the motor and it purred just fine.  Nice low speed control.

I tore the truck completely down to check all axles and bearings.  Cleaned and re-lubed everything.  Truck move nicely on the track with drive axle removed.  Also with the axle (all spurs and axles moving) installed seems good.  I have to hold that axle down because the motor mount plate is removed..

Going back together AGAIN right now.  

All together.  Everything checked and rechecked.  Bearing flats just the way they need to be.  Flywheel spins really nice by hand. 

Powered it up and locked up in about 1 revolution.    It will do the high speed thing once it breaks away.  

It just does not like low speed against torque.  

So, thrust bearing, not enough current, or bad motor seems to be the choices.

The next step is to swap the motors to make sure there is no wear on the armature worm that may be causing the problem. After that, replacing the #27 worm gear assembly, and the #24 thrust bearing would be advised. You can try swapping these parts out from the front truck first, to see if they solve the problem.

Larry

Just to close the loop on this issue.  Turned out to actually be an idler gear on the truck.  It had considerable slop between the stud and the inner race of the gear.  The gear turned eccentric instead of concentric.  The front truck had same issue but to a lesser degree.  This used engine must have been used a lot.  New trucks will take care of this problem.