Practical Marriage

The beauty of the Briggs and Stratton Little Gen Set


| March 2006



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Small generator sets first became popular in the mid-1930s. These first generators were primarily used to recharge 6-volt wet-cell batteries to operate lights and a radio for evening entertainment on farms without electricity. Later, they would be used for many different purposes including powering independent lighting by direct connection. The gas engine washing machine was very popular in rural America by this time. Consequently, in 1937 the Briggs and Stratton Co. came up with the idea to combine a washing machine engine with a generator to do both jobs at once. At that time, their washing machine engine was known as the Model WM, so this new unit became the Model WMG and was called the "Start-Charger washer motor." Not many of these units still exist, possibly because of their location under a washing machine, although records show that 9,242 were made.

Being an avid Briggs and Stratton collector, I had been looking for generator units made by the company to add to my collection. By February 2002, I had collected a PC 100 and a PC 304 generator set when I came upon an ad on the Antique Small Engine Collectors Club website (www.asecc.com). The ad was for a small WMG engine and generator. The seller said the generator was probably not restorable, but the engine was loose and the tag on the shroud indicated Type 20651 and serial no. 1064. He said the generator was very rusty but I made an offer for both.

I had previously found a rare copy of the operating instructions for a Start-Charger washer motor at an engine show in New York. Having studied this manual carefully, I was very excited when the box finally arrived in the mail. Unfortunately, since the generator and engine were shipped in the same box without packing, they banged together, breaking the carburetor. The shroud was badly dented, and the engine/generator base was so bent they would not align when put together.

After this initial disappointment, I went to work stripping the generator, as it seemed to be the biggest challenge. The generator casing was missing and so was the top of the circuit breaker. As a result of these missing covers, the generator's insides were very corroded, either from sitting under a washing machine for many years or perhaps being out in the elements. I checked out the armature and field coil, and as I expected both were shorted out and would need rewinding.

The original casing would have had an inside diameter of 5-1/4 inches with a 1/8-inch wall thickness. I could only find 6-inch tubing to fabricate the new casing, so I cut a section out of the side; but when I welded it back together it formed a teardrop shape. By squeezing the casing in a vice to an oval shape then welding a bead up the inside, I was able to bring it back to a proper circle that fit the field coil core perfectly. Next, I made an endplate by turning down a 1/4-inch steel plate on the lathe, then drilling cooling holes and a center hole for the bearing. An automotive frost plug was pressed backwards into this hole, then filled with two felt washers and pierced with an oil cap to make a bearing cup.

New mounting studs were made from threaded rod, and a new insulated brush mounting plate was made from a type of plastic cardboard to replace the deformed original. The brushes were in good enough shape to reuse with new springs attached. The generator went back together after some persuasion.