Athearn locomotive running slowly

[blue92rs]

Hello all! I have two older Athearn Blue Box GP 35 locomotives. One I have had nearly 20 years, and the other I aquired on Ebay a short time ago. The one I bought recently is about the same vintage as my original. They run like two completely different animals!!! When I put the Ebay loco on the track, the first thought that came to my mind is "what in the world is wrong with my original one!!!" The Ebay loco has great low speed performance and only needs about half throttle to get up to a good speed. My original will not even start moving until half throttle. I pulled out my Fluke meter and tested current draw to each loco. The Ebay unit hums nicely along at half throttle, drawing at most .29 amperes at 9 volts. Full throttle peaks at about .58 amperes at 13.2 volts, then settles back to about .29 - .31 amperes. (scary fast) My original loco draws .31 amperes at nearly 10 volts and it is not even moving!!! The only way to get it going is to open the throttle fully. At that point it draws .59 - .60 amperes at about 12.6 volts. I read through the "Athearn Tune Up" article that another member gave me the link to. I gave the unit a good teardown, clean, and lube. I then did the top clip replacement without reinstalling the cab light. The improvement was noticable, but barely. Current draw went down to about .57 amperes. Anyone have any thoughts? Thanks again in advance.

 

[BNSF dude]

I'm guessing the one you got before has the old "Alpha-Jet" motor. The new one you have must have a more recent one. Might I reccomend a repower?

 

[kjd]

It could have a broken armature wire or two making it a 4 or 3 pole motor instead of 5. Make sure all the little wires are connected from the cummutator (the part the brushes rub on) to the coils. I think there should be 10 wires total. You can try to solder it but it is easier to replace the motor. You can turn the flywheels easily with your fingers?

 

[wvg_ca]

sometimes the grease in the gear sets gets stiff with age, or there may be some binding in the gearset or drives...
you should be able to give he motor a little spin on the flywheels by hand, and the whole assembly should turn fairly easily... you can use the 'better' loco as a reference to see how a free assembly will spin..
if it's tight, best way to check is to pull the motor, and try by itself, and check front back truck gearsets by themselves as well..

..enjoy..

 

[blue92rs]

I'm guessing the one you got before has the old "Alpha-Jet" motor. The new one you have must have a more recent one. Might I reccomend a repower?

Well, I checked everyones suggestions, no binding, everything spins freely, no old grease in the trucks, (I cleaned and lubed them thoroughly before I posted my question), all the armature windings are intact and the frame-to-truck contacts are very clean. So, I called Athearn and the tech I spoke to there gave me the exact same explanation as BNSFdude. The older motors draw way more current than the newer ones. The two locos I have were from the transistion period to better motors. I am considering a repower, but do not want to get the wrong motor. It is hard to tell on Ebay what is what. The fellow @ Athearn told me that the current motors they offer as parts now are a Hex Drive and there are many fitment issues that arise when attempting to repower a model as old as mine with the newer motors. He said I would have to upgrade the trucks as well. At that point I may as well spend the money on an entire locomotive... Any suggestions as to what to look for when searching for a better motor that will drop in would be greatly appreciated... maybe someone has one they would be willing to sell???
Thanks, Steve

 

[kjd]

You don't need to upgrade the trucks. If you got a new motor with a hex drive you could either get the new drive lines as well or swap flywheels with the old motor. I don't totally buy the old motor vs new motor theory either. I have at least 60 Athearn engines from 1987 to 2008 and I haven't seen any dramatic speed differences between any two. Some are slower and some faster but not so different I can't run them together. I should add all mine are the brass colored narrow motor not the wide silver motor.

 

[UP2CSX]

I do buy the motor problem. I've had a few of the older motors go bad, Paul, and it's usually in the armature, just as you said. I've found it nearly impossible to fix the problem and the best thing to do is junk the motor. You can get a new Athearn motor for about $10-$15 on e-bay and, except for making a mounting pad that's a little higher than the original, so it laines up with the drivetrain, it's not a hard replacement. NWSL also sells much better quality can motor replacements but these require more work including milling the frame. The cost will approach a new RTR Athearn so, unless this locomotive has great sentimental value, I'd try an Athearn motor replacement or make it into a dummy.

 

[kjd]

I forgot to mention I have had one motor go bad and it ran as the original post described. It had a broken wire between the coil and the commutator. I tried to solder it but it was too short and they are coated with epoxy so I gave up and replaced the motor. That is the only problem child I've had beyond the usual Athearn issues. I figure that is not bad for getting close to 25 years of playing with trains.