showcrop
Well-known Member
I was at a tractor pull three weeks ago with my '57 960 which has won me a number of trophies over the years. It was a two day affair at the big local fair. Before my hook on Friday evening I just happened to check the setting of the high speed jet and found that it was at 3/4 so I opened it to 1.5 and thought nothing more about it. I got started down the track and she started to cut out. She cleared up and I got about 2/3 of the way down and she started to cut out again. I lost my momentum and didn't go much further. It seemed like a rich mixture, so next AM I drained the carb to check for foreign material, but the gas came out clean. I checked for air obstruction and choke operation, but every thing checked good so I went over to ignition. I borrowed a rotor but no joy, so I canceled my entry for that day. A few days later I got back home and got into it, again checking ignition. I found a few potential problems that I took care of, then due to a FD rescue call and the ignition being left on I burned up the EI module. So I ordered up the new EI, and when it came in installed it and she fired right up. Yesterday I started her up to do some tuning but she was back to running very "fat" again. So as I was checking more things out and went back to the carburetor, it suddenly dawned on me that it needed to be set at 3/4 turn. A few years ago I had taken it to a local well respected shop for a rebuild and they told me that they put the "correct" main jet in. The one that had been in it was incorrect. Well, running on my dyno at the time had shown me that they were wrong and that it needed to be at 3/4. The memory of that had faded away.
