Restoring a 1-3/4 HP Nelson Bros. Little Jumbo Gas Engine

By Staff
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The Little Jumbo belted to a color-matched feed mill. Luke took this shot in neighbors Gil and Wanda Barnes' garden, noting it's much nicer than his.
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Luke Kissell restored his 1- HP Nelson Bros. Little Jumbo over the course of a winter, a sure-fire way to ward off the winter blues. The end result is very nice, indeed.
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The Little Jumbo as it looked when Luke bought it
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Sandblasted and starting to come apart.
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The cylinder head is removed in preparation for cylinder and piston work.

Circa-1915 1-3/4 HP Nelson Bros.
Manufacturer: Nelson Bros. Co., Saginaw, Mich.
Year: Circa 1915
Serial number: 17574
Horsepower: 1-3/4
Bore: 3-1/2-inch
Stroke: 5-inch
Flywheel diameter: 16 inches
Flywheel width: 1-1/2 inches
Governing: Hit-and-miss
Ignition: Low-tension magneto and igniter

In the late fall of 2003, I was perusing the contents of my new engine storage shed (the project I worked on all summer) to find a suitable engine in need of restoration for a wintertime project. I’m the type of person who saves any indoor work for the worst part of winter, so I can spend as much time as possible outdoors when it’s nice.

The previous winter, I totally renovated my bathroom and worked on a few engines in need of attention. This winter, I wanted to custom-build some oak cabinets for the kitchen and restore an engine, but which one? Fortunately, there’s no lack of engines in the shed needing restoration, so I picked one and started planning.

I acquired this particular engine in April 2002, at a sale in Cambridge, Md. The advertisement for the sale said 50-plus engines in various condition should be on hand. But when I arrived and looked over the offerings, I was a bit disappointed. There was not one engine in ‘good’ condition. All of them were rusted, and a lot of them were missing parts, stuck, etc. Nevertheless, I had to bring something home with me. I ended up with three fairly complete engines; a dishpan Fairbanks, a throttle-governed Witte and a Nelson Bros., the latter which is the subject of this story.

Little Jumbo
The engine is a 1-3/4 HP Nelson Bros. Little Jumbo Type P, serial no. 17574. I decided early on I wanted it to be mostly original, with a couple of personality twists – I was going to paint it and stripe it to my liking. Also, I wanted to replace the original steel grease cups with new machined-brass cups that I had been saving. I needed a Webster magneto, a gas tank and wanted an original muffler, so I started searching.

The gas tank was easy: in stock from Lee Pedersen. I found a man in Florida who was selling magnetos and had several types, and I decided on a Webster Type MM, which has the double horseshoe magnets.

I received two replies to an Internet advertisement I placed for a muffler. One gentleman had brass reproduction mufflers (a good piece of information for the future), but my first reply came from a man who had an original. I sent a check, and the muffler was mine.

I disassembled and sandblasted the engine, and after cleaning the hopper I sprayed everything with two coats of ‘Extend Rust Treatment’ – a primer paint made by Permatex that is supposed to inhibit rust. The piston, rings and cylinder looked surprisingly good, so I honed the cylinder and cleaned and reused the rings. When in doubt, I like to have a machine shop grind the valves, but the Little Jumbo’s valves were ready to go after a quick lapping of the faces.

The wrist pin bearing had turned in the connecting rod, so I drilled a new oil hole in it for lubrication. The igniter points were misaligned, so I fit a small washer to get them to line up properly. I also ground them true. I made all new gaskets, and I replaced all the small springs on the engine with new ones.

Next came painting. I applied three coats of gray spray primer to everything, and I brush painted the bulk of the engine with no less than five coats of Rustoleum Painter’s Touch Apple Red paint. I applied four coats of gold paint for the stripes, and I sprayed the magneto bracket and valve springs gloss black.

In between painting, I worked on the cart – it probably cost me less than $20. I paid $10 for the front wheels two years ago at the Chambersburg, Pa., steam show flea market, and the rear wheels came from a walk-behind lime spreader I found on a jobsite where a house was set to be demolished. When 1 removed the wheels from the spreader, I searched through my collection of parts and, lo and behold, the spreader wheels matched the flea market wheels! Amazing.

I made the cart bed from genuine Maryland red oak I had left over from repairing the wooden bridge in my driveway. I cut, planed and beveled the oak on a router table, then made four dado cuts for the two cross members. I routed the axle boards with a 1/2-inch round bit to accept the 1/2-inch cold-rolled steel rod I used for axle shafts. U-bolts secure the rods to the wood. I then applied four coats of polyurethane to the oak. The handle is 3/8-inch hot-rolled steel rod.

When I finished with the painting, it was time to start reassembling the engine. I positioned the gas tank and the engine on the cart to mark their bolt locations, drilled the holes and secured the tank and engine to the cart. At the same time, I measured and fabricated the check valve and fuel line. I wanted to buy new oiler glass and gaskets, so once again I turned to Lee Pedersen. I polished all the brass, first with a wire-wheel brush, followed up with ‘Happich Simi chrome polish’ and ‘Never Dull,’ a wadding-type cleaner/polish. I bought the decals from a Gas Engine Magazine advertiser. Finally, I bought a small feed mill at auction and painted it to match the Nelson.

And there you have it, another engine project complete and ready for a busy show season!

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