Posted by Dan-Ca on April 23, 1998 at 03:06:10:
In Reply to: Carb adjustment, JD "B"& IH "H" posted by SteveW/swMI on April 19, 1998 at 17:51:39:
: As a slave to modern rigs, I'm stuck with not knowing how to adjust carbs on old rigs. My '46 JD "B" will start & run but can't get it to respond to the throttle or idle without oscilating (up/down running). The IH "H" is hard to start. Have cleaned the carb but it's still a bear to get going and, when it runs, it runs fast. How do I slow it down? Details apprreciated.
For the J.D. "B" get the service manual # SM-2004 from John Deere. The up-down rpm problem is called "hunting" or "searching". Here are the possible problems: 1. Throttle rod adjustment wrong. Take rod loose at carb. see if linkage is allowing carb to return to idle position. 2. Binding action in linkage either at carburetor(cotterpin catching on body of carb.) at governor(remove linkage, test movement of gov. arm for binding. If binding disassemble govenor. 3. Carb. stop screw set wrong. 4. Engine flooding, check float setting. 5 Bad fuel or restricted supply of fuel.(check for water in fuel or old fuel.) Gas setting in carb. turns to varnish, which can cause this. Use fuel stabilizer (which is really just kerosene-smell it!) I use about 1 oz. per gallon of gas. Run tractor until carb. empty after shutting off fuel every time you use tractor. 6. Sticky valves. See repair manual for this. For the farmall check the linkage. It may not be allowing the carb. to return to idle position.