Check for worn bearings. If the armature bearings are worn, the armature can contact the field and the engine will not start without a push. If this has happened, you are going to have to install bushings to take the wear out of the bearings. 45 years ago, I had a 2-4-2 switcher that had been run without lubing the motor bearings, and it had the problem you describe. I put a plastic bushing in the upper motor bearing and all has been well since then. Lack of lubrication is one of the ways to really destroy a good engine. While we are on the subject of lubrication, I strongly recommend that no one use lithium grease or any other grease, for that matter. The greases always dry out and leave a mess. Automotive motor oil works well and doesn't have this problem. I am using 5W-20 and have used motor oil for 50+ years without a problem. You can even oil the commutator without a problem.
If you can get the armature out of the motor, look for wear marks on the periphery of the armature. Also, see if the bearings are loose.
Bruce Baker
If you can get the armature out of the motor, look for wear marks on the periphery of the armature. Also, see if the bearings are loose.
Bruce Baker
