F to N, and R to N: Engine lunges

Something is causing it to require too much power and time to advance to the neutral position.  Could be several things.  A common one is too much finger pressure on the drum.  It should respond fairly crisply with only about 10VAC at the rail.  And of course even more so with more power.  

Make sure the reverse unit coil is being fed directly from the front and rear truck rivets and not from part of the motor circuit which will cause the delay while the current builds up to operate it.

In can be the angle of the contact fingers, possibly bent by cleaning, or in an attempt to make better contact pressure. Maybe a sticky plunger in the coil or weak coil as well.

another trick to try is move the lock out lever about half way. This will move the flapper assembly closer to the coil and require less energy to pick up the armature flapper.

Rick - here's my two cents! 

First - You should not apply oil to the ends of the drum. Any viscous material will only serve to slow the action down, and you will most certainly pay for it down the road when the oil attracts dirt. I would take a Q-tip dipped in alcohol and clean the oil off both ends of the drum and clean both slots where the drum ends run up and down.

The fact that your engine starts at a low voltage and gets moving is a good thing, so I wouldn’t do anything to the engine to delay its start. But I would focus on tweaking the e-unit for better performance.

When I finish cleaning/overhauling my e-units, I test them by hooking the coil up directly to my ZW and just cracking the throttle – generally about 8 volts. The e-unit should operate quickly and consistently with the pawl/drum assembly operating flawlessly time after time as seen in the first half of this video. Feel free to ignore the 2nd half of the vid, it was made just to show progress to one person on a repair.

Since you have already cleaned your e-unit, you should test it and compare its speed to the one in my video. If they are the same, and you're doing the test at 8 volts, then you may have to live with the problem. Others will tell you that some engine & e-unit combinations typically demonstrate the same issue you're seeing. In my opinion, it's a design issue.

George

Quick edit: there is a slight possibility that you may have connection issues, so when you test your e-unit, leave it in the engine frame and connect power to the collector and frame - note the performance. Then retest it hooking directly to the e-unit coil terminal and e-unit frame. If you see any difference in response, i.e. sluggish action when powering from the collectors, you may have some bad connections coming from your collector(s).

I am 100% with George on the lubrication of the drum, never oil it. If you might want to lubricate the drum use a powdered Teflon or a bit of graphite on the ends of the drum where it comes through the side of the reverse unit.

Ray

For lube where lube shouldn't really be needed, try "T-9". A non messy dry lube spray. It dries to a very thin, see through white, wax-like film.  Teflon based and it doesn't attract dirt, penetrates near any gap or crack when wet, "plastic safe"(carrier leaves what looks like water stains on some though). It was made by Boeing for lubing and ice prevention on airplane flaps, baydoors, etc.. Ice falls right off, if it even manages to form.

  A tad pricey but you don't need much at all.  A can will last decades if reserved for train use. I've used it on everything from rusty hinge pins on stuck van doors not opened for a decade, to pinball flipper coils where the coil plunger's guide sleeve had side load wear holes so began jamming (temp. till a new sleeve came).... and trains. An amazing product imo.