A Unique Briggs and Stratton Model FH Conversion

By Staff
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by Gas Engine Magazine Staff
B&S Model FH Conversion

B&S Model FH Conversion

Builder: Gary Richardson, Buna, TX (originally Briggs & Stratton Corp., Milwaukee, WI)
Year: Circa 1928 (FH production ran 1925-1933; slant fin FHs were early production engines)
Serial No.: N/A
Horsepower: 1/2hp @ 1,800rpm
Bore & stroke: 2-1/4in x 2-1/4in
Flywheel: 9-1/2in x 1-1/4in
Ignition: Spark plug with battery and coil
Governing: Hit-and-miss with flyball governor (originally throttle-governed)
Cooling: Air

People express themselves in a wide variety of ways. Some paint pictures, some compose music, others build houses, while yet others craft fine jewelry. A few, like Gary Richardson, retrofit old engines, converting them into hit-or-miss engines.

The speed of many small, 4-cycle engines is governed by the throttle opening. Weights are mounted within the flywheel, and as the flywheel rotates, centrifugal force moves the weights outwards, in turn working the butterfly valve in the carburetor to maintain the desired speed of the engine. In earlier hit-and-miss engines, an external flyball governor connects to the exhaust valve via linkage. When the speed of the engine is below a given level, the exhaust valve operates as normal, staying closed on the intake stroke as the piston draws down, creating a vacuum that opens the intake valve for the admission of the fuel/air mixture, which is then ignited (the “hit”) to produce a power stroke.

When the speed exceeds the desired level, the governor holds the exhaust valve open. With no vacuum in the cylinder, the intake valve stays closed and there is no admission of fuel/air (the “miss”). As a result, hit-or-miss engines have a distinctive sound when running – “bang, whoosh, whoosh, whoosh, whoosh, bang, whoosh, whoosh, whoosh, whoosh.” One or two heavy flywheels serve to maintain a more-or-less constant speed.

A close-up of the sideshaft and governor, which acts on the L-shaped arm to latch out the exhaust valve.

Changing it up

Gary Richardson lived from 1937 to 2013 in Buna, Texas, which is located in the Piney Woods in East Texas, not far from the Louisiana border. Gary’s passion was taking a conventional engine and converting it into a hit-and-miss. One of the engines he liked to work on was the Briggs & Stratton Model FH.

The B&S FH is a small engine producing 1/2hp at 1,800rpm. Its vertical cylinder has a 2-1/4-inch bore and a 2-1/4-inch stroke. Some are called “slant fin” engines because their cooling fins extend on a diagonal from the cylinders. The B&S FH engine was produced from 1925 to 1933 in Milwaukee, Wisconsin.

A close-up of the face cam that acts on the exhaust valve rocker arm, and the bevel gears on the sides haft and governor.

To convert a B&S FH engine to hit-or-miss, Gary removed part of the crankcase and mounted the cylinder horizontally. Working with a foundry in Ohio, Gary created his own brass castings, which he finished and mounted on the engine. These included a side shaft, gears, a fuel “mixer,” a flyball governor, flywheels, an oiler and grease cups, and wheels for a cart. The finished product with its gleaming brass appendages was truly a work of art.

Gary would convert several of these engines during the fall and winter months. The following summer, he would load up a number of them in an old station wagon and drive to Portland, Indiana, to one of the annual Tri-State Gas Engine & Tractor Assn. swap meets. He usually sold all of his engines before the swap meet even began, and he sometimes delivered one or more engines that he had already been commissioned to build.

The fuel mixer. The flap on the bottom is the choke.

Not alone

Gary wasn’t the only person retrofitting old engines like this. Builders including Edd Fillmore of Osage City, Kansas, and Pete Nichols Sr., of Spencer, West Virginia, produced similar engines. Along with Gary, these builders also converted larger engines, such as the Empire and Rock Island.

Gary sold one of his converted Briggs & Stratton FH engines to Glenn Evans, a collector in Bandera, Texas. While owned by Glenn, the engine was seen and admired by Becky Smith of Fredericksburg, Texas, who expressed an interest in purchasing the engine if it ever came up for sale. Although he was an experienced restorer of old engines, Glenn was never able to get the engine to run to his satisfaction.

The FH’s original crankcase was cut away.


Eventually, he made an even trade with another collector for a different engine. That collector, Terry Watson, who lived near Long View, Texas, was able to make the engine run smoothly and he displayed it at shows. Becky saw the engine at a show after Terry acquired it and got it running, and she again asked to have a chance to buy it if it ever came up for sale. After Terry passed away in 2015, his wife, Cecilia, contacted Becky and told her that Terry had instructed her to offer the engine to Becky after his passing. Becky immediately purchased the engine and she now proudly displays it at vintage engine and tractor shows.

Older woman in a black shirt showing her blue and gold engine off at a Steam Engine show.

Gary may be gone, but thanks to collectors like Becky, his fascinating creations are still being enjoyed today.

The Briggs & Stratton Model FH and a Little Briggs & Stratton History

Briggs & Stratton Corp. started as a partnership between Stephen Foster Briggs and Harold M. Stratton in Milwaukee, Wisconsin, in 1909. Initially, the pair focused on supplying parts to the young and booming automotive industry, producing components including igniters and switches. The company formally incorporated in 1910, and continued making parts for the auto industry.

In 1919, Briggs & Stratton bought the rights to the A.O. Smith Motor Wheel and started building it as a power source for bicycles and small carts. This was the first in what would become a long line of Briggs & Stratton engines.

An old engine with some newer parts.

Briggs & Stratton’s first in-house engine was the flathead P series, introduced in 1920. Small, reliable, and easily adapted to a variety of household duties from powering washers to small mowers, the P set Briggs & Stratton on its course to become a major manufacturer of small engines.

The overhead valve FH series was introduced in 1925. These had a mechanically actuated exhaust valve and an atmospheric intake. Throttle governing was used to control engine speed, and they were fitted with a fan and shroud for cooling. Some sources say the FH was only equipped with rope pull starting, but it’s clear that foot starting was offered early on. Early models featured so-called “slant fin” cooling fins, while later engines had horizontal cooling fins. Production continued until 1933.

A later FH with horizontal cooling fins. The FH was made from 1925-1933.
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