American Flyer engine goes forward for 2 or more seconds before reverse unit sequences.

One cause can be the finger tension is too tight causing too much friction on the drum and it rotates slow and at a higher voltage. Some of the new replacement fingers are too stiff.

I'm assuming that you are referring to a "postwar" American Flyer locomotive. I would start by checking the wire that goes from the pickup directly into the reverse unit. Sometimes as they age they will break off and not make good contact. 

Are you using as Gilbert transformer? These have a start voltage of 7V. They were designed like that so the reverse unit pawl will actuate firmly as soon as voltage is applied to the track. I have several well running engines with good reverse units I can run around my layout without actuating the reverse unit. The layout uses ZW-L's for track power which do not have a threshold minimum voltage. At 4V indicated on the track the engine will run slowly and smoothly just under the actuation voltage of the reverse unit which is 4.5 to 5V.

In any event, from the description provided it sounds like your engine may have a stiff reverse unit as discussed above.

I'm using a ZW post war transformer.  I wiil check the reverse unit per your suggestions.  On another AF engine I put a bridge rectifier in series with the motor, dropping the voltage to the motor only by about 1.2 volts..  That did several things.....reverse unit engaged immediately,  brighter light, and thicker smoke.   But would rather do this current engine per 'factory specs'.  Will let you know the results.

Dave in Atlanta

The postwar ZW has close to a 1V minimum voltage when rotating the handles away from the stop position. That could be a contributor to the reverse unit performance you are experiencing.

Can you tell us which locomotive you have with this problem? Sounds to me you have a two position reverse unit.

Tom @AmFlyer my experience differs from yours.  A healthy, unmodified postwar ZW starts around 5.5V "open circuit."  With a significant load it's possible to get readings down near 5V, but definitely not 1V.  Some other transformers such as the RW, 1033, etc., have multiple binding posts, some combinations of which give a "low range" output that starts at zero.

Some Lionel locos with "e-units" behave similarly to what the original poster described.  A couple of examples I tried built in the late '40s would travel several inches at low voltage before the E-unit would cycle.  One trick you can do with a ZW is hold the spring-loaded direction control and "pop the clutch."  In other words, hold the direction control, turn the handle up to 7 or 7.5V and then release the direction control.  The E-unit will immediately cycle into neutral and the loco should only move a fraction of an inch, if at all.

Drummer3 posted:

The reverse unit doesn't engage immediately, so the engine goes forward (or reverse) for several seconds.  Any suggestions to correct this?

Thank you.

 

Dave try this. Set or lock your reverse unit to the forward only. Every time you start the loco it will go foward every time. Still  what locomotive are you using?

It could be a less than optimally operating postwar (pw) electro-mechanical reverse unit (ru) due to excessive finger pressure (as mentioned) or other contributing factors.  That would lead to more power having to be applied than ought to be necessary.  Most Gilbert pw ru's in good tune activate dependably with between 9-11 VAC.  In some cases your engine will respond and start moving with less than that.  If you bring up the power gradually the engine will start to move prior to the ru actuating.  Try putting 10 or volts to the track to kick in the ru in before the engine has a chance to start moving.  Test with a meter how much power you're having to apply to actuate your ru.  

I once had a 336 FEF that was so efficient, smooth, strong, smokey, and fast that it would outpace even the most efficient pw ru.  I installed a Dallee #400 universal electronic reverse unit.  From then on I  had no problem reversing it standing still.  That's b/c 400's require far less power to reverse that their ACG counterparts.  (They also apply power to the motor in a smooth gradual fashion so your starts are take-up-the-slack yard-goat easy.)  Smooth sailing after that.  On the other hand, I've had plenty of pw engines in which a well-tuned pw ru worked fine.   Still have a few.  

Be well and have fun running your trains.  

Dave

So how would you fix Dave's problem?

My engine is the AF 315   4-6-2.   I once had a the AF 336  4-8-4 with the same problem. The engine would run around the whole loop (slow speed) w/o the RU engaging.  Solved this like in my previous post above using a bridge rectifier.   I wonder if there is a way to add some type of capacitor discharge circuit in the tender to give the RU an extra boost.

Milan posted:

So how would you fix Dave's problem?

The reverse unit really needs to come out and be stripped down and totally cleaned.

Clean the drum so that all dirt and grime is removed and polish the tracking. Also clean out the segments on the ratchet on the drum as well.

If the fingers are in good shape then clean/polish the ends that touch the drum. I then adjust the angle of the fingers to about 30 degrees, it works for me but others may have a different approach to the desired angle.

While it is still in pieces use a Q tip to clean any grime from the brass pawl that engages into the drum. Also use a Q tip to clean the top right upper part of the oval hole on the main frame body where the pawl engages and stops once energised. It is crud in this corner that stops the pawl from dropping when power is closed. You can do this without stripping down as well. You will be surprised as to how much dirt collects at this point.

Rebuild it all back again and do not use any oil on anything, it just gums things up and defeats any other work that has been done.

Milan,

1. Lock it in forward as you suggested, unless of course he'd actually like to use reverse, or...
2. Clean, tune-up, and optimize the functioning of the existing pw ru -- much like UK described, but I'd also recommend making sure the pawl's pivot elbow is freed-up and clean (I'd even suggest ever so tiny a drop of light penetrating oil on it such as CRC PowerLube, that alone can sometimes surprisingly enhance the ops of a cranky pw ru), and then live with it, there are harder things in life to get used to, or...
3. Try DRUMMER3's bridge rectifier method (I have no experience with it, but he does), or...
4. Replace the pw ru with a Dallee 400 -- but remember, if you put electronics in an engine, any engine, then install derailment/short-circuit protection on your layout.  I recommend 7A fast-blow fuses or PSX-AC's.  

Dave

I have been running Flyer trains for 63 years. Never had a need for a bridge rectifier on my motors.  That is driving the motor with DC. I find AC to be ok  I grew up in house that was wired for DC only.it was on the lower east of Manhattan and part of Edisons DC grid. In 1955 The grid was changed to AC. Then I was able to get an electric train set. I chose  American flyer  still have it. 

Dave clean you reverse unit, track,tender wheels. Good luck.

Hi Milan,

A bridge rectifier can also be used to insert a 1.2 voltage drop "resistor".  I am not using it to change over to DC, but  to place it in series with the motor.   So, after reading everyone's comments, it appears my best option is to clean / rebuild the RU. 

Dave in Atlanta

The rectifier in series works wonders, especially on the Baldwins, as that motor is engineered for a lower start voltage (an error by the ACG engineers).  Cleaning the reverse unit is also important. On the Baldwins, you only need to move one wire, so the change is easily reversible (pun intended). But the rectifier needs to only effect the motor, not the headlight nor smoke unit (easily done on the 5 wire engines). I've not actually had the delayed reversing problem with the steamers, so I would think that cleaning & servicing should solve the problem.

The other option is using an actual AF transformer with the dead man throttle .

 You can apply more voltage to sequence the Reverser, if required.

  Of course the Reverse unit must be fully cleaned and serviced

   Al