'Just Parts Engines'

Correct? No. Complete and Running? You Bet, and Not Bad for What were only ...

| July/August 2003

  • 4-1/2 HP Jacobson
    The 4-1/2 HP Jacobson restored as a 4 HP Bull's Eye (left) and the 3-1/2 HP Jacobson.
  • 4-1/2 HP Jacobson
    Even if it started life as a 4-1/2 HP Jacobson, the Bull's Eye is an excellent restoration and a great-looking engine.
  • 3-1/2 HP Jacobson
    The 3-1/2 HP Jacobson in its finished glory. It's almost impossible to tell that many of its parts were fabricated out of steel.
  • Fabricated cylinder

  • Igniter port
    This shot shows the outer plate in place over the bushings on the head studs and the igniter port.
  • Parts built for the 3-1/2 HP Jacobson
    Parts built for the 3-1/2 HP Jacobson included the head, crank guard, muffler, igniter, igniter trip arm and inlet manifold.
  • Fabricated cylinder head
    The fabricated cylinder head, nearly finished.

  • 4-1/2 HP Jacobson
  • 4-1/2 HP Jacobson
  • 3-1/2 HP Jacobson
  • Fabricated cylinder
  • Igniter port
  • Parts built for the 3-1/2 HP Jacobson
  • Fabricated cylinder head

One day a few years back I was invited to look at a couple of engines a fellow collector kept behind his shop. It seems we collectors always need one more, so I was pleased to go along for a look.

There in the high grass were the picked-over remains of two Jacobson-built engines. One was a 4-1/2 HP engine base with a cylinder, hopper, flywheels and crankshaft, and the other was a 3-1/2 HP base with crankshaft and flywheels assembled. They were both missing most of their small parts, not to mention major items like heads, pistons, rods and crank guards - and the crankshaft bearing cap was missing from the 4-1/2 HP. 'They were just parts engines when I got them,' he said. Both engine bases had a curious chunk broken out of them, and everything was suffering from exposure to the elements. I was, of course, interested, and he said he'd let me know if he was going to sell them. One month later they were mine.

Now What?

I wasn't sure what I would do with them, but I knew at the very least the flywheels from the 3-1/2 HP could be used on my grandfather's Bull's Eye, which has incorrect flywheels he put on years ago. And I figured the other wasted relic could be sold to a fellow I met on the Internet who could use the base and hopper of the 4-1/2 HP to repair his Bull's Eye, the victim of a tornado. Now, understand that I do like the Jacobson-built engines, and resurrecting the 4-1/2 HP engine did cross my mind. But I knew that to bring either one of these back to life would require a truckload of bits and pieces.

I offered the 4-1/2 HP parts to my long-distance friend, but he couldn't decide how much to offer for them. After hanging up the phone with him, I began to wonder if I should keep it for myself. Resurrecting it would take time, money, lots of perseverance, a little help from some friends (I have no machine tools) and it would take ingenuity to make the missing parts, which I knew would be difficult to find.



I called a collector I know in Pennsylvania, whom I knew had some Jacobson parts to sell. 'Yes, I've got a head and a piston - maybe a sideshaft support and governor parts,' he said. I picked them up the next Saturday. I didn't inquire about parts for the 3-1/2 HP (one challenge at a time, you know), but he said he had a hopper and a rusty cylinder for a 3-1/2 HP lying off in a corner. I didn't pursue any of this, because 1 knew I had my hands full with the 4-1/2 HP project. Indeed, I did have a lot of work to do!

Starting In

Disassembly of the few parts I had for the 4-1/2 HP revealed the engine had been run with both flywheels loose. The machine shop said they could take a skin cut out of the flywheel bores and build up the crank with spray metal to get a fit. I told them not to hurry, as there were other problems to overcome. Most curious to me was the missing crankshaft bearing cap, the sheared cap studs, and the 1-by 2-inch, three-cornered chunk broken out of the crankshaft bearing saddle. I fabricated another cap, and I figured if I poured my own crank bearings I wouldn't need any machine work on the cap. Drilling out the broken studs and brazing a piece of steel into the bearing saddle got the base plate into useable condition.