The only gasoline internal combustion engines that most people have in their households are either in cars or lawnmowers. That naturally leads to the thought: What if you took the tiny mower motor and installed it into an automobile? That’s what one young intrepid YouTuber did, and the results are glorious.
My coworker Jason Torchinsky and I have been talking about installing a pull-start lawnmower engine into a car for years now, but it looks like YouTuber Carson Duba has beaten us to the punch. And he appears to have done quite a nice job:
What we’re looking at here is an early 1980s Dodge Ram 50 powered by a 6.5 horsepower, 8.1 ft-lb overhead-valve single-cylinder engine sold at Harbor Freight for $120. The tool store, you will be surprised to know, does not actually list “automobile” as an application for this motor. Here’s the full list from the store’s website:
pressure washers, cement mixers, compressors, mowers, log splitters, vacuums, tillers, water pumps, chipper/shredders, generators, blowers
The Dodge had apparently been sitting in the young wrencher’s friend’s yard for a while, so the friend just gave it away. Carson Duba decided to have some fun with it, stripping out the old motor, leaving not much more than the steering intermediate shaft and brake master cylinder. He then built a platform that ties into the original engine mounts, and that carries the single-cylinder engine.
That engine, which can slide on the platform thanks to slotted holes, has a centrifugal clutch on its output shaft, which sends power to a five-speed manual transmission via a sprocket and a chain. To get a 60-tooth sprocket on the transmission end, the YouTuber welded a shaft to the transmission input shaft (unsurprisingly, it was difficult to weld it perfectly straight), and then made a bracket so that the shaft could ride on a bearing (this bracket ties into a custom mount that holds up the front of the transmission). The big sprocket sits on the end of that shaft, and the tension of its chain is set by sliding the motor along the slotted holes in the platform.
The whole build is far more elegant than I expected for something as silly as a lawnmower engine in a junky old truck. The choke is hooked up to a nice slider on the dash, the original cable running from the gas pedal actuates the tiny engine’s throttle, and there’s a fairly nicely-packaged pull cord that goes through the fender, with a handle in the wheel housing that starts motor. A simple kill switch on the dash cuts it off.
The young mechanic even made his own door panels using material from a shower, and he demonstrates in the video that the truck works in both reverse and in a forward gear, even if it only drives about 20 MPH.