Stuck motor, possible solution

Like most of us I guess, I have a few second-hand engines with motors that don't turn. Separating the motor from the mechanism is quite fiddly so those that are not being used by the children sit in a box waiting for service. 

Yesterday I had a look at such an engine from someone else's collection:

• off - rolls freely - good
  

• on without battery - wheels locked - good
  

• clean contacts,  insert fresh battery - no sound, no motion - bad (common fault after 15+ years disuse)
  

• Then I thought I would try the 9v battery and snap lead that happened to be on the bench. I touched the leads on the contacts with a small spark. Then again and the motor sprung to life. Then I replaced the usual 1.5V battery and it all worked as it should.
  

I guess that the motor had become jammed by hard grease and dirt and once free it kept going.

I tried this with another four old stuck engines. Three of them responded.

Hope this is of some use.

(now to change some traction tires and return the engines to the kids.)

[Super]

Good job Densha. Many of us here use the 'Jump Start' method using a 9volt to shock stubborn motors to life after sitting for long periods of time.

Good job Densha. Many of us here use the 'Jump Start' method using a 9volt to shock stubborn motors to life after sitting for long periods of time.

Indeed we do. Always try that first.