Bypass the e-unit...

Yes you can do that.  Center rail to one brush, other brush to input of field winding.  Other field winding end should already be on Chassis ground.

If the fingers are bad on the e-unit and need to be replaced anyway, the easiest way to do this is to cut the wires already attached to the motor and field, as close to the e-unit fingers as possible, and connect them as listed above.  You will also need to take the center rail off the e-unit tab.

If it runs in reverse, just swap the brush lead connections to get forward.  G

     A possible solution is to remove the shell, unsolder the e unit from the motor, so that you just have the three contacts on the brush plate, without any wires connected.  You may as well remove the e unit while you are at it.  Looking at the brush plate, count from left to right and number the left solder contact as #1, the center contact as #2, and the right side as contact #3.  What you need to do is strap the center contact #2 to #1 (shorting the two together).  Take a wire from the roller pick ups, that was originally connected to the e unit, (your power pick up point).  You want to connect that wire to the unused contact #3.  If I remember correctly, this connection will get the loco to run in forward only.  If it runs in reverse, then switch the strap from #2 & #3, and connect the pickup wire to #1.  This should get you working.

     I have two 2020 locos, and one 681, and I have had to refurb the motors, but have only done this, with the motor totally removed from the frame, and used a transformer connected to the ground lug of the field coil on one lead, and then connected the other transformer lead to the unused post of the motor, and checked the operation of the motor.  Then I reverse the strapping, and connect the lead to the other side of the motor contact.  Hope this well get you running.

What do you think is wrong? I bet the spring failed. You can bypass it, but...

Turn it off,(or back on) the lever touches a contact and rides up on it, seating. Feel for unseating(easier IMO) to off ("loser" in off position)  

 Now if you turn the loco pointing up, each end over end turn, and tapping, so the E-unit plunger falls, you may be able to cycle it to fwd. if careful.

Or if plunger is jammed, you might be able to turn the drum into position with something pointy.

 Undisturbed it will be ok a while.

A bypass? A rewire is safer. Remove wires as you go if needed.

 One wire from the stationary outer windings goes to the frame(fyi) , the other goes to the e-unit, remove it* from the E-unit side.

One brush wire goes right to the roller. the other gets the wire*(above) from the outer windings. Running in reverse? Just swap brush wires around to correct it.

quote:

Looking at the brush plate, count from left to right and number the left solder contact as #1, the center contact as #2, and the right side as contact #3.  What you need to do is strap the center contact #2 to #1 (shorting the two together).  Take a wire from the roller pick ups, that was originally connected to the e unit, (your power pick up point).  You want to connect that wire to the unused contact #3.  If I remember correctly, this connection will get the loco to run in forward only.  If it runs in reverse, then switch the strap from #2 & #3, and connect the pickup wire to #1.  This should get you working.

If it's a 1946 model, the brushplate will have five terminals. Ignore the outermost terminals, which are connected to the jacks on the back of the brushplate, and are used to control the E-unit. Here is the service manual page.

Please, pardon my being so forward. Would it not be better to only disassemble the engine one time? Remember the old saying, "Haste Makes Waste". Christmas is only seven-days away. Relax and enjoy the holiday season...Just a thought .

God Bless,

  "Pappy"

Might not have an on/off lever either right

A 1946 Turbine or Berkshire does not have an on-off lever for the reversing unit. The reversing unit is controlled by a set of jacks and a plug mounted on the brushplate. See the service manual page I linked above.

A turbine shell is held on by three screws, If the original poster is comfortable repairing Postwar Lionel trains, and knows how to solder, then in my opinion, temporarily wiring it to run forward only is no big deal.