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Cast-iron flywheel and PTO pulley
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Dave Bush and his refurbished Briggs & Stratton FEO 505 engine
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The FEO 505 engine's brass priming cup
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The exhaust valve is rocker-arm
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1/2-hp Briggs & Stratton FEO 505 engine
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The carburetor side of the FEO 505 engine
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Thumbscrew Type P carburetor
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Brass tag mounted on the blower housing

Nestled in the middle of the Susquehanna River south of Harrisburg, Pa., Hill Island is only accessible by boat. The folks who live there prefer it that way. A few roads and vehicles are now scattered across the island where electricity wasn’t available until the mid-1960s. Prior to electrification, stationary engines and gasoline-powered appliances performed essential tasks on Hill Island. From mowing grass, pumping water to washing clothes, internal-combustion engines pulled their weight on the island.

Many of those power units were retired to the proverbial back shed when electricity finally reached the island, while others were sold or scrapped. Luckily, more than 70 engines were discovered in a shed in the late 1990s by an island resident who at the time was a machinist for the Bethlehem Steel Co.

The machinist told co-worker Dave Bush of Dillsburg, Pa., about the newfound engines on the island and initially offered them all as a gift to him. Dave, who prefers antique tractors, declined the offer. ‘I had no idea what to do with that many engines,’ he admits. Within a couple weeks, the machinist scrapped all the engines except one, which he placed in the bed of Dave’s pickup truck. ‘I really didn’t know if I wanted the engine, but it was unusual, so I bought it because I couldn’t just accept it as a gift,’ Dave recalls.

He identified the engine as a Briggs & Stratton FE series, but the old engine wasn’t like any other Dave had seen. The engine sports a large cast-iron fuel tank base, larger than on most FE engines. A brass priming cup is plumbed into the intake port of the head – another unusual feature. The engine isn’t an orphan like many odd, turn-of-the-century engines because the parent company still exists. Yet, it’s a model unlike anything the old-iron collector had seen – and it can’t be traced to any known Briggs & Stratton product line.

When Dave brought it home to Dillsburg, the engine wasn’t stuck, but it had no compression. He oiled the motor and put it on a shelf where it sat for a year. ‘I brought it home, but really I had other projects going, so I forgot about it,’ he remembers. In July 2001, Dave noticed that the Gratz Area Antique Machinery Association show in Gratz, Pa., was featuring Briggs & Stratton engines.

‘That was all of the motivation that I needed to take a closer look at that unusual engine,’ he says.

Close inspection

Dave’s engine has a flywheel on each end of the crankshaft. That may not be unusual, but one flywheel is made of aluminum with fins that double as the cooling blower. The magneto is connected to the backside of the blower. The heavier, cast-iron flywheel includes a PTO pulley.

Like all FE series Briggs & Stratton engines, the intake valve is actuated by suction from the piston as it moves down on the intake stroke. A cam-driven push rod activates the exhaust valve through a rocker arm. Once the head was removed, Dave discovered the piston’s seal was still intact as he turned the flywheel with one hand tightly clamped on the cylinder opening. The cylinder wall was smooth, but the engine had a compression leak, which meant the valves weren’t seated properly. After thoroughly cleaning and lightly lapping both valves, he reinstalled the head and the engine’s compression was perfect.

A spark plug inspection came next. Dave turned the flywheel, which in turn heated the magneto, generating high-tension voltage. Next, he cleaned the fuel tank and carburetor and then started the engine. He sprayed carburetor cleaner into the brass priming cup to run the engine, and within half a day he had it running on gasoline pulled directly from the fuel tank. To his delight, there was no bearing noise and the engine ran perfectly.

Dave’s engine – like all FE series engines – uses a Type P carburetor manufactured by Briggs & Stratton that consists of a bronze U-shaped tubular casting, which sits atop the fuel tank. Fuel is drawn from a tube that drops from the bottom of the U tube into the tank. One arm of the U tube is attached to the intake manifold while the other is attached to the air cleaner. Dave’s engine uses a butterfly choke in the air cleaner tube just above the carburetor, which is controlled by an external thumbscrew. The Type P carburetor doesn’t have adjustable jets or needle valves, so the choke is used to adjust the air-to-fuel mix in the engine’s operating range. The bronze carburetor also has twin throttle butterflies, one in each arm of the U. The same throttle shaft actuates both, and together they control the air and fuel feed. The throttle is lever-adjusted with a particular setting maintained by the governor, which is located behind the cast-iron flywheel. After all the hard work on the little oil-burning engine, the FEO ran especially well considering that it sat in a barn for about three quarters of a century. Surprisingly, the engine never required any new parts. The restoration’s hardest part, Dave says, was cleaning the carburetor and removing the head to lap the valves.

Model mystery

With plenty of time before the Gratz show, Dave prepared the engine for painting. While doing so, he deciphered the engine’s complete serial number as FEO 505. To Dave’s surprise, research turned up nothing about this serial number. Remarkably, the FEO wasn’t listed in any publication or Web resource. Dave learned only that FE engines were built in 1925. His engine looks similar to the FE, but has a brass priming cup and larger fuel tank. Nothing could be learned about the ‘O’ in his engine’s model name, but many Briggs & Stratton serial numbers have an extra letter before the numerals. The extra letter often indicates some special engine characteristic. For example, an ‘H’ or ‘M’ indicates the engine is a high-speed or marine variant of that particular model.

Dave still doesn’t know what the ‘O’ modifier in the engine’s serial number means, but he has a possible explanation. Since many engines with priming systems were designed to run on kerosene, all-fuel or distillate, their designs include a method for starting them on higher-quality fuel, such as gasoline. Once started and warm, the engines are switched over to the less-volatile kerosene. In fact, many all-fuel or kerosene engines have a separate, but smaller, tank for gasoline rather than a priming cup. Dave suspects that the ‘O’ in his engine’s serial number must stand for ‘oil.’ That would explain the reason for the priming cup, which isn’t necessary to start the engine with gasoline. Further, a 10- to 15-percent drop in horsepower results while burning kerosene, which means the throttle must be wide-open to achieve the rated 1/2 hp of the 2.25-inch bore by 2.25-inch stroke engine. In this configuration, a larger fuel tank would be beneficial since a kerosene-burning engine must run harder to produce the same horsepower as gasoline.

Painted pretty

Dave also found original red paint on the inside of the blower shroud. He matched the color to a commercial red paint and coated the crankcase, fuel tank, blower and parts of the flywheel. He left one small area of the original paint intact for comparison. The cylinder and running surfaces of the cast-iron flywheel and PTO pulley were painted silver, which matched the engine’s original color scheme. Dave also polished the bronze carburetor and brass priming cup.

Understandably, Dave’s rare engine was a big hit at the Gratz show. Both thrilled and frustrated at the same time, however, he wasn’t able to discover any additional information on the FEO 505. Fortunately, time is on his side. Just as the little Briggs & Stratton languished out of sight in a remote barn on a river island, the missing model information must be hidden somewhere as well. With a little luck, that information will be found, unlocking the mystery of the castaway oil-burning engine. FC

Dave would very much like to find out more about this orphan oil burner and its unusual fuel system and serial number. He can be contacted by e-mail at or by mail at 37 Carroll Drive, Dillsburg, PA 17019.

Oscar ‘Hank’ Will III is an old-iron collector and restorer who retired from farming in 1999 and from academia in 1996. He splits his time between his home in Whittier, Calif, and his farm in East Andover, N.H. Write him at 13952 Summit Drive, Whittier, CA 90602; or call (562) 696-4024; or e-mail:

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