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

Wintertime restoration

| July/August 2004

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.

Rod Campbell
2/25/2009 10:14:37 PM

Hi from down under (New Zealand). I have just aquired a Nelson Bros model P, Little Jumbo, plus a spare missing some bits.I am interested in material on restoring this engine and perhaps some parts at a reasonable price, if anyone can help. I intend keeping and showing this as well as my recently restored Lister D and I have an Australian Blaxland Pup single watercooled 2 stroke marine engine in good order,for restoration soon.