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7 hp Fuller & Johnson Restoration

This circa-1914 7 hp Fuller & Johnson was found complete in a yard but needed work.

| June/July 2017

  • Richard Adams' Fuller & Johnson.
    Photo by Richard Adams
  • Richard Adams' circa-1914 7 hp Fuller & Johnson as found was complete but needed work.
    Photo by Richard Adams
  • Richard with the Fuller & Johnson at home just after purchase.
    Photo by Richard Adams
  • The replacement piston (at left) was sourced from a John Deere 620.
    Photo by Richard Adams
  • The replacement piston is the correct bore size, but taller than the original, so Richard machined it down as much as possible. He ended up with a higher compression ratio as a result, 4.5:1 versus 4.1:1 stock.
    Photo by Richard Adams
  • Machining the cylinder head. The original valve guides were bored out to take larger stems.
    Photo by Richard Adams
  • The cleaned cylinder/water hopper during setup for the new sleeve.
    Photo by Richard Adams
  • Centering the connecting rod on a mandrel in preparation for pouring new babbitt.
    Photo by Richard Adams
  • The cylinder/water hopper, painted and bolted to the engine base and ready for further assembly.
    Photo by Richard Adams
  • The crankshaft installed and shimmed, complete with connecting rod, piston and crankshaft oilers.
    Photo by Richard Adams
  • Front view of the finished engine.
    Photo by Richard Adams
  • The air filter is a Donaldson oil bath filter from a Caterpillar engine. Richard made the aluminum adapter for it.
    Photo by Richard Adams

Circa-1914 7 hp Fuller & Johnson

Manufacturer: Fuller & Johnson Mfg. Co., Madison, WI
Circa 1914
7 hp @ 400rpm
Bore & stroke:
5.5in x 10in
Flywheel dia:
32in x 2-3/8in
Igniter w/coil and battery

After restoring 11 antique tractors, I thought that an old hit-and-miss engine might be fun to restore. A friend, Scotty, just happened to have an old engine of unknown make half buried out in his yard and offered to sell it if I would restore it. It was not stuck, but had no compression. All the castings appeared to be there, and I could find no cracks. After looking through a book on old engines, I found this engine to be a Fuller & Johnson 7 hp made in Madison, Wisconsin, around 1914. Its history, or what it might have been used for, is still unknown.

Getting to work

After getting this 1,200-pound monster home on my small utility trailer I pressure washed it and started its disassembly. After taking off the head I removed two handfuls of rust from the cylinder. The bore and valves were badly rusted and the valve guides were badly worn. After removing the piston and rod I found the rod journal also to be badly worn. The igniter was rusted shut and missing springs. The good news was that all original parts were still on the engine and no cracked castings were found.

Next, I removed the cylinder block from the frame. To remove the crankshaft, the flywheels and timing gear had to be first removed. It sounds easy, but the flywheels and flywheel keys were really stuck. I used heat and penetrating oil daily, trying to pull the keys with a sliding hammer. I thought the keys would never budge, but after 11 days they started to move a little. Finally, after a few days’ work the keys came out. I was cautioned not to use too much heat on the flywheel as the spokes could expand and crack the rim.

To break the flywheels free from the crank, I spun the assembly and quickly slid a wood block between the frame and crank journal, stopping the rotation quickly. The inertia of the flywheel broke the bond and I was able to push the flywheel off the crank with a hydraulic jack. The remainder of the engine disassembly went well. With all parts off, I sandblasted everything except the main bearings that I protected with several layers of duct tape. After close inspection I still found no cracks.

Machine work

The machine work ($$$!) came next. I wanted to have the cylinder bored and a sleeve installed so that the original piston could be reused, but no one made a sleeve 5-1/2 inches x 21 inches long, and I didn’t want to put two sleeves together. I started looking for an oversize piston that would work and found that a John Deere 620 used the same 5-1/2-inch bore. I called around and found a used John Deere 620 piston, 0.125 inch oversize, which was about the amount needed to clean up the bore. As John Deere 620 pistons are sold in pairs, I was lucky to find a supplier with only one piston that he sold me at a fair price. The piston came with rings that were still useable.


Gas Engine Magazine A_M 16Gas Engine Magazine is your best source for tractor and stationary gas engine information.  Subscribe and connect with more than 23,000 other gas engine collectors and build your knowledge, share your passion and search for parts, in the publication written by and for gas engine enthusiasts! Gas Engine Magazine brings you: restoration stories, company histories, and technical advice. Plus our Flywheel Forum column helps answer your engine inquiries!

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