Regarding Flint & Walling, Gas Engine Magazine August/September 2006.
Here are more names found on nameplates that could be hiding an Alamo engine: Blue Line, Dairy King, Duplex Mfg. Co., Duplex-Superior, G.F. Avery & Sons, Hoosier, Lunt Moss Co., Magnolia, Monarch Gas Engine Co., Moody, R.M. Wade & Co., Royal and Victor.
I found this on a website (www.angelfire.com/ny/buzzcoil/page21.html) about Alamo engines. Notice the Hoosier is listed as an approved agent. These serial numbers would indicate that Flint & Walling used them until 1913.
Jim Zook's engine (page 12) is marked "Hoosier/Flint & Walling" and has serial no. 12523-1.
According to the Alamo Mfg. Co., pre "Alamo Blue Line" 1 to 120 HP engines made from 1900 to 1913 have serial no. 1 to serial no. 13,769. Many engines of this period were vertical engines.
In regard to nametags and serial numbers, all Alamo engines left the Alamo Engine Co. foundry with a serial number stamped on the front of the water hopper for the smaller size engines, or stamped on the cylinder head for the larger size engines. These serial numbers were awarded consecutively from no. 1 on the first engine to no. 116,000 (plus or minus) on the last Alamo engine built, and this independently of the engine's horsepower rating or of the destined approved agent. It was the agent's responsibility to put the brass nameplate on the engine. This nametag would show the agent's company name, the engine's rated horsepower and RPM and also the serial number that would simply duplicate the serial number already present on the engine.
One slight variation about the serial number on the nameplate is found on Alamo-built engines sold by the Rock Island Plow Co., as this agent was also selling other companies' engines, and in order to prevent possible confusion, they simply added the letter "A" for Alamo, in front of the serial number on the nametag.
The plot thickens in this mystery: I have now seen a complete decal. It is a beautiful decal in color, it has a redish metalflake backround with gold trim and lettering. The most important thing is that it says "Reg. U.S. Pat. Off." My thought is that you don't patent a decal you patent the product. This would lead one to believe that Flint & Walling did indeed make their own engine.
The engine this decal is on is the finest "original" engine that I have seen. It appears to have always been inside, has plenty of good paint and the crankshaft guard, and is mounted on the original flat board with complete battery box, just like the glass negative picture from 1915. The serial no. is 2712-K, so I still have some bragging rights about my engine being the oldest, with serial no. 1857-K.
Flint & Walling Inc.