I am looking for a Walbro LTA100 carburetor for the S-12D on my Bolens 1250. The LTA100 is stated to be the carb required for tractors with a serial number below a certain value, and my Bolens' serial no. is below that value. Have been looking on ebay and googling it, but no luck. Any suggestions on how to find one, or what to use if I can't find one, would be welcome.