In answer to Stan Reid's recent inquiry about Dick Seibert's engine, it is a Coldwell Cub engine. It supplied power for Coldwell's Cub Motor Lawn Mower, No. 28-V. It was built by the Coldwell Lawn Mower Company, Newburgh, New York. First produced in 1928 and lasting until 1938, there were two major versions, which may be identified by the carburetor and type of clutch. The first production Cubs used a Tillotson MS-16A carburetor and had a dry clutch between engine and mower. In 1935 the Tillotson MS-31B carburetor was adopted and an oil clutch was put on. This version was used until 1938 when production was dropped. This is the only way I have found to tell approximate date of manufacture.
The Cub engine is a beautifully constructed piece of machinery with tapered roller bearings and a bronze crankpin insert. It runs at its designed speed of 1,100 rpm as smooth as could be. Although not an old engine as engines could be, it is well worth the collector's attention as a special interest item and an excellent sample of American workmanship.
The serial numbers for these machines are on the mower plate, which is on the sheet metal cover over the transmission. Coldwell, as far as I know, didn't put the serial on the engines. Unlucky if you have only the engine. Of possible interest is that my lawn mower is No.2V4052 and was one of the ones built between 1935 and 1938. As far as I know I have an original replacement carburetor and my mower uses an oil bath clutch.
For more information I suggest a letter be sent to Century Lawn Mower Service. Century was Coldwell's service outlet and when Coldwell went out of business, Century took over service. They still have literature on the Cub and a few parts for it. The manual I received was very detailed and included complete information on the Cub's American Bosch, Type FY-8, Ed. 1 magneto.