Starter tesing

[jmbrodsky@domain.elided]

Danny,

     The weight of the armature, and the tremendous amount of torque that the
starter can deliver are the factors that make it jump around when you try it.
It should do that.  It will spark, but only AFTER you open the contacts.  
Actually, electrically, a spark only occurs AFTER you OPEN the contacts, so hold
it on there good!

     When you get over the fact that that thing wants to jump away, the bendix 
(the spiral drive that pushes the pinion into the cap) should kick out some, and
the motor should spin, pretty fast.  When you take the power away, the pinion 
should retract into the case, and continue to spin for maybe a second or two.  
This is key, if it stops right away, you need bearings, or another method to 
free up a stiff armature.  If the spin seems like it's surging under power, then
you maybe have a dead (one or more actually) commutator.  These are the little 
copper segments in a cylinder at the opposite end from the pinion.  Clean in 
between the plates with a small pick (don't poke, ,just pull through the goo), 
and then polish with krokus cloth, or a rubber eraser.  Don't gouge the 
commutator, it should be very smooth so as not to eat your brushes up.  The 
brushes are available at any auto store ($4.00 is high for the pair) and the 
bearings too if you need 'em (Usually like $5 or $10 apiece).  What fails is the
little disk inside the solenoid (the soda can sized thingy along the side of the
motor).  It's about the size of a quarter in there and gets a few more holes 
with every start.  Also there are two large copper lugs that contact the 
'quarter' and these get eroded too!  They are reversible though, so you can 
usually use them some more.  Ie. Use the other side that isn't eroded.  To check
the commutator, look for shorts (with a meter) between consecutive copper 
segments.  Each 180 opposed pair, should be isolated from any adjacent segments.
If you get a short, then the windings coud be bad, or the commutator itself.

     Very rarely do field windings crap out (the ones still in the motor can 
when the armature is out), you can check those with the meter too!.

     Good luck, and I hoe some of this helped!


     -Joel Brodsky

         '76 IHC Scout II 345/tf727
         '75 IHC Travelall 150 4wd 392/tf727
         '72 Chev Carryall 3dr 4wd 350/th350 sold, but not forgotten.


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Date: Thu, 5 Feb 1998 12:31:18 -0500
From: "Danny Anderson" <bturnip@domain.elided>
Subject: starter testing

IH'ers,
I am turning to you for the correct procedure for testing the starter off
the battery.  I know this is a basic test- I thought I knew how to do it.  
Also, what can happen if the jumper cables are hooked up incorrectly? :)  
I tried hooking the jumper cables up like I thought they were supposed to
be connected.  But, instead of the gear (the gear that would turn the
flywheel, bendix?) shooting out and spinning like I expected, I got sparks
and the starter literally bucked and flopped for a second.  Almost like I
was electrocuting it!  Yikes!
Somebody please pull out of my pool of automotive ignorance and tell me
what I did, what happens now, and what I should have done.
A thousand thanks.

danny
bturnip@domain.elided

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