225E e-unit problems

No oil on sliding solenoid coils/plunger, ever! Maybe a light graphite powder or drylube. But a better solution is to add the strong return spring from an E unit that runs a side sliding plunger. One is a very light weight cyclone shaped spring which sits on the tip of the plunger shaft, bottoming inside the coil tube pushing the plunger out, and/or one sitting between the coil guide tube and plunger head, again pushing out. While the plunger is out again, check the coil plunger guide tube inner surface for wear too. Sorry I don't have a part number for springs handy, last time, about 15yrs ago, I just eyeballed a little stronger "outer" one at the local "real" hardware store, E-unit in hand.  

I have found that when a plunger hangs up, that changing the drum fixes the problem. The drum wears in an imperceptible way that all the usual "fixes" do not see or address. Change the drum and see what happens.

Larry

Something that may help is to replace the E unit in your 225E with a rebuilt E unit, as it is over 70 years old if it is the original one. I did that to my 224E and now I have a great running pre-ww2 engine. The drum kept slipping out of the frame that held it in, even after a couple attempts to repair it, so I replaced it with a rebuilt.

Lee Fritz

As Adriatic wrote, an e-unit should never be oiled.

That written, a little oil recently applied to the ends of the e-unit drum should not cause the plunger to hang up.

There are several potential root causes to your problem.

Some folks believe that residual magnetism can build up in the plunger, and demagnetizing the e-unit will resolve the issue. This has not been my experience.

Sometimes the teeth on the e-unit drum develop grooves that seem to catch the pawl, stopping it from dropping. Sometimes the teeth can be filed to eliminate the grooves, other times its best to replace the drum (I remove the drum to file it).

Most likely is an accumulation of dirt and oxidation on the plunger and in the center of the e-unit coil. Someone could have put oil in this area before you purchased the locomotive. You can try spraying non-lubricating cleaner into the plunger hole. When I run into this problem, I break down the e-unit, clean out the hole with qtips wetted with mineral spirits, and clean the plunger. If the plunger is oxidized, it gets a light sanding with fine emery cloth. It is rare to have the problem after such a cleaning.

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I have always been chicken to take the e-unit apart but may have to.  Any advise or tricks for disassemble would be appreciated.  It's back in the engine right now, but it doesn't come apart with screws to the best of my memory.  Also considering the rebuilt approach, but seems a shame as clean as it looks. 

Try an electric cleaning spray first.

Purchase an ST-303 E-unit spreader. Reproductions are fine. Train Tender gets $3.50 cents for theirs.

The spreader has a cam on one end that is placed between the sides of the e-unit and worked to pop the sides apart without having pieces fly all over. I usually place it right next to the spacer bar.

Gettting the lower (2 finger) contact and drum out is easy.

I find removing the side (4 finger) contact and plunger a bit more challanging because the sides need to be spread rather wide.
(Perhaps someone can share their tricks).

When reassembling the unit, the loose side should snap into the spacer bar. If the hold is poor, I rest the attached side on a block (must lay flat by the space bar) and dimple the loose side with a sharp center punch placed right in the seam between the bar and the e-unit side. One sharp blow will hold it.

Lionel made a special vise to hold the e-unit for reassembly. There are also a couple of aftermarket ones. I own one, I don't use it. I prefer to just hold the unit in my hand.

One last tip. I completely disconnect the e-unit and remove it from the locomotive for servicing.

I agree with CW. I use an old wood chisel, 3/4" wide, to spread the E unit as near to the cross pin as you can get. I would unsolder the wires, it saves profanity when you are done and one of the wires is broken off. I would clean the plunger, and the tube the plunger is drawn into by magnetism, then take the plunger and put it on an anvil and give it a couple taps with a small hammer, just to shake up the electrons in the plunger and remove any residual magnetism. Others may laugh, but that is what I do. Then clean the holes that the drum pivots in, and the slots that the plunger guides slide in, and use a nail file to make sure that there are no metal burrs  on the inside of the E unit frame. A new drum would be best, as disassembling the E unit isn't something you want to do more than once. Let us know if we can be of any assistance.

One more time - Thanks to all for the support and help, this is truly a great forum.  I now have a working e-unit and the engine is running fine!!  Wasn't that hard once I dived in.  Special thanks to  CW for the tip on the ST-303 spreader.  Got one and it works well.  Also Larry for the comment about the pawl sticking in the drum.  I believe that was my problem also.  Put in a new drum, cleaned a small patch of rust off the plunger, cleaned the drum fingers and put her back together.  Also thanks to OKHIKER for mentioning YouTube!  I should have thought of that, but didn't. 

Gene