Jacobsen Engine ‘The Twin’ Found at Last

Andrew Mackey details his interest in Jacobsen engines, a 20-year search and the restoration of a rare 2-cylinder Part 1 of 3.

| June / July 2020

Jacobsen “4-Acre” reel type mower with 24-inch cut and 1-1/2hp engine. Aptly named, the “4-Acre” meant the user was able to mow four acres in an 8-hour day.

This story actually starts 56 years ago, when I was 8 years old. My parents took us kids to many antique shops all over the East Coast. At a shop in Lafayette, New Jersey, I happened across a 1952 Jacobsen Lawn Queen reel-type mower half-buried in weeds behind the shop. It seemed to be all there, albeit sun-faded and a bit rusty. I went inside and asked the owner if it was for sale. He seemed to not know it was out back, so he asked me to show him. He thought about it for a minute and said, “five bucks and it’s yours.” “Sold,” was my reply, and I nearly ripped my pants trying to get my hard-earned mowing money out of my pocket.

My dad was not too happy with my purchase — it nearly didn’t fit in the trunk of his Peugeot 403! When I got home, I cleaned the mower off, mixed some gas and oil for the fuel, filled it up and gave the recoil starter a pull. To my surprise, the Jacobsen 2-cycle engine started right up and purred like a kitten. For a few years I had been using a REO Royale reel-type mower to cut grass for spending money. The reel and bed knife were well worn, and the mower was not doing a great job. I decided to give the Jacobsen Lawn Queen a try on my next job, and I was hooked. It was a lot lighter, seemed to be more maneuverable and was just as quiet as the REO model 211 4- cycle cast iron engine.

I actually used the Jacobsen for nearly 10 years and finally sold it after I bought a Jacobsen Turbo Vac rotary mower. The Turbo Vac had an 18-inch steel disc with four small triangular blades mounted on the rim, giving the mower a 21-inch cut. It had an aluminum deck which made it light and maneuverable in tight corners. It also had two blower fins that added air movement to the discharge, making the mower a vacuum at the same time – hence the name. It did a better cutting job and a much better job picking up clippings than a friend’s new Snapper mower.

I ended up selling the Lawn Queen to a neighbor who still uses it to this day. As far as I know, it has never been or needed to be rebuilt, and has been decoked only twice. Decoking is the removal of carbon from the exhaust ports, a common problem with older 2-cycle engines that used a relatively heavy oil-to-fuel ratio. In this case, 16:1 or one cup of oil to one gallon of gasoline. I have been hooked on Jacobsen engines and mowers ever since.

Turbo Vac modifications

My next mower was a 30-inch cut Jacobsen rotary mower. A huge beast with a steel deck, it was no lightweight, but it did cut a wide swath which made for fast cutting of large lawns. A friend and I used it many times in the course of our landscaping jobs. It did not do a very good job blowing out the clippings and only made some mulch out of leaves encountered on the grass. I decided to try mounting four of the blower fins that were mounted to the Turbo Vac mower to “The Beast” to see if it then would do a better job with the cleanup. My big mistake here was not doing the job of installing them myself. I had bought them and asked my friend John to install them and I arrived at his home just in time to see if indeed the mower did a better job at cleaning up.


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