[AT] Case VAH won't run; carb issues

[Dean Vinson]

I was up at my dad's farm last weekend and continued tinkering with the old
VAH.  This is the tractor we had when I was a kid, and which I bought back
in 2006 about 20 years after my dad sold it.  It's still up at the farm and
I haven't made many trips up there to work on it, so don't know much about
its recent history.

When I first brought it back to the farm in 2006 it started and ran very
well, but it hasn't run since sometime in 2008 I guess, not really sure when
the last time was.

On my last two visits, a few months ago and just this past weekend, I
disassembled, cleaned, and reassembled the sediment bowl and fuel line, and
there's a good fast flow of fuel through the line when it's disconnected
from the carburetor.  Put new gas in the tank, which had been very very low,
maybe empty.  Disassembled and cleaned the air cleaner.  In the process
discovered the air cleaner was mounted too low in its vertical adjustment
range, causing the air pipe to be about 1/4" out of alignment with the carb
intake pipe, which over some long number of years had reduced the rubber
connecting hose to a twisted rotten oily mess.  Fixed all that stuff.
Confirmed that there's a good spark, and that there's a reason to be careful
with your finger placement when testing for spark.  Cleaned off the exterior
of the carburetor, but haven't opened it up.  

After all that, the tractor will start right off and run great for a second
or two, then die and won't fire again until some more time passes.  I
fiddled with the main jet and idle adjustment screws but couldn't get it to
do any better.  So my theory is that something is clogging the carburetor,
and the next step is to take it to a shop for a rebuild or to try a
maintenance kit myself.

Any recommendations?  It's a Marvel-Schebler TSX-597.  There's an
in-progress photo at
http://www.vinsonfarm.net/photos/Case_VAH_carburetor.jpg.

Thanks--

Dean Vinson
Dayton, Ohio
www.vinsonfarm.net