[AJD] B timing solved

[Dean VP]

Nick:

This is good. Let's think positive and assume your coil in the magneto is
really good. There is a way to manually test the magneto to see if it is
producing a hot enough spark but it may take two people to do it. I don't
remember if this is a manual or electric start tractor but try to find out
how far the spark will jump external to the sparkplug first. 

But first make sure the plug wires are connected right. If the magneto is
timed and installed properly the top wire on the cap should go to #1 or the
left cylinder and the bottom one to #2 or the right cylinder. If the magneto
is installed 180 degrees out then the wires will have to be reversed. 

Hold the end of the sparkplug wire close to a bare part of the metal frame
of the tractor. Maybe a 1/4 of an inch or so while the engine is being
turned over. The spark should jump across this gap with a bright blue spark
and make a snapping sound. If you have trouble getting the spark to jump or
the color isn't blue but yellow then the spark is weak and further work
needs to be done at the magneto. If you are getting a good spark this way
then remove the plugs, attach the plug wires to each plug, ground the base
of the plug to some bare metal on the tractor and test to see if you are
getting a strong spark at the gap in the plugs. Not getting a good spark at
the plug gap? Then the plugs need to be cleaned or replaced. If it is good
then there is a good chance the ignition is working properly. However, there
still is a possibility that the plugs aren't firing under compression.
Replacing the plugs is the only way to verify this as a problem.

Now if you are not getting a good spark from the magneto through the wires
then one of several other problems may exist. Wires can be bad?  If they are
carbon based wires throw them away and get copper core wire versions
immediately. Once the wires are proven to be good then moving back up the
serial chain back to the magneto cap check to see if you are getting a good
strong spark out of the cap. This can be accomplished by partially pulling
the wires out of the cap and turning the motor over to see if you can see
and hear the spark jump from the cap to the wire. If not the cap may be bad
and the copper conductors inspected, cleaned and rechecked. Maybe even a cap
replacement may be necessary. But before that remove the cap, check to see
that the rotor is clean and in good repair with all the contacts clean and
in good condition.  Then check to see if there is a spark being developed
when the points open after being closed. This can be done manually or
watching them while the engine is being turned over. No spark, then check to
see if the point contacts are clean and closing properly. An ohm meter would
be really handy here to check to see if the there truly is 0 ohms across the
points when they are closed. If not clean and adjust the points until they
truly reduce the resistance to 0. There is also a remote chance the
condenser may have shorted out or is leaking badly. To test that just
disconnect the condenser temporarily. The tractor will run with it
disconnected but shouldn't be left disconnected. 

Now if none of these steps solve the problem there is a good chance the coil
has gone bad assuming you are getting a good impulse from the spring
mechanism on the coil. You can hear if that is working or not. You heard
that sound when you manually timed the magneto.

The bottom line is just work your way back from the spark plugs until you
isolate the problem.  Good luck.  Hope this helps.

 

Dean A. Van Peursem
Snohomish, WA 98290

I'm a walking storeroom of facts..... I've just lost the key to the
storeroom door 


www.deerelegacy.com

http://members.cox.net/classicweb/email.htm



-----Original Message-----
From: antique-johndeere-bounces at lists.antique-tractor.com
[mailto:antique-johndeere-bounces at lists.antique-tractor.com] On Behalf Of
nick_solomon at infostations.com
Sent: Saturday, February 12, 2005 11:15 AM
To: Antique John Deere mailing list
Subject: [AJD] B timing solved

I think Ive got it just about as close to in time as humanly possible
after 6 tries I got the slot flat, for some reason It didn't want to mesh
the first 5 tries, and it still pops a little bit,but won't start.  I tore
into my magneto and tested everything which in the past had been ok, and
my coil seems to be shorted out. is it still possible to get a bit of a
spark with a bad coil? has anybody every tried to rebuild their own coil?
tips? Im low on funds right now and need to just get it going to move it
so I don't kill myself pushing it( the day it stopped running I had it
parked smack in the middle of my drive blocking my garage where my truck
is parked... which normally Id use to pull it to where it needed to
be)love how luck works huh?

Nick

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