342AC

If it isn’t the smoke unit wiring shorting out it is possibly the wires soldered to the field coil touching the inside of the shell. See if you can re-arrange those soldered connections to be lower or put some insulation over the top of the field coil and the soldered connections and see what happens.

Gilbert did actually put a protective cover/tape over the smoke unit lugs on a number of engines, not sure if all though.

I don't have experience with S gauge but try putting some tape temporarily over those solder lugs and find out if that's the cause.

I'll try insulating different things one at a time to find the culprit.   Also having trouble getting the boiler front to stay on.   It has a small rivet thingy to hold it on and it does not like to stay put.

I have put a little bit of hot glue on the rivet.  If you try to adjust the rivet and shell it may break.  The hot glue works for one time.  If you take the boiler front off it will take a new shot of the glue. 

Original Gilbert engines sometimes came with masking tape at the points of shorting possibilities, smoke unit and field wiring. The tape is usually dried and thru disassembly and age is usually missing. Any type of tape capable of insulating should be OK.

Rich

richabr posted:

Original Gilbert engines sometimes came with masking tape at the points of shorting possibilities, smoke unit and field wiring. The tape is usually dried and thru disassembly and age is usually missing. Any type of tape capable of insulating should be OK.

Rich

Was it on the shell or the field/smoke unit wires?

Roundhouse Bill posted:

I have put a little bit of hot glue on the rivet.  If you try to adjust the rivet and shell it may break.  The hot glue works for one time.  If you take the boiler front off it will take a new shot of the glue. 

Good idea.  I'll try that.

Was it on the shell or the field/smoke unit wires?

I've only observed it on the component.

Rich

Well, I added the insulation and all is well.  I went ahead and rewired the e-unit with a new harness, because they had some thick wires on it. Also needed to replace the bottom fingers.

Hot glued the boiler front and it stays where it's sposda.

Here's a picture of the engine.  As you can see, it is a 342AC  with knuckle couplers and a 343 front coupler.  Doofus me didn't realize that the link coupler versions didn't have a coupler on the front.

Great to hear you got it running.  As mentioned, some postwar AF steam engines came with a thin black ~5/8" wide strip of paper over the smoke unit contacts held into place with masking tape.  I found that if you can't reuse the original paper strip (too saturated with fluid, etc.) manilla file folder material and fresh tape do the trick nicely.  Have the area and smoke unit body clean and dry before installation.  Also some have been found with similar insulation on the ceiling of their cab roofs to prevent field connection points from contacting the shell.  Not all, but some.