I recently picked up both a TN-26 and TN-27, and after initial cleanup, tore apart the carbs and cleaned them real well. Now after reassembling everything both engines are doing the exact same thing. I can get them started, but they are backfiring now and as such will not stay running longer than about 30 seconds. I went through the ignition systems (cleaned and adjusted points) and they both look good. I am fairly certain it was something I did with the carb rebuild as I was able to get the one running for short periods of time (10-15 seconds) before it would act like it ran out of gas, but it never backfired. I am not a complete novice with these carbs as I have rebuilt a couple HD-25's which are similar. Any thoughts or suggestions??