Vintage two stroke Lawnboy push mower
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I had the chance to get a 40+ year old Lawnboy push mower running. It was bought in the mid seventies and hadn't run in ~30 years or so, and sitting outside for who knows how long. My first thought was no Ethanol back then, so how hard can it be? It was stored under a pine tree with no direct sunlight, so was thinking maybe even the primer will still work and it did.
First thing was to make sure it wasn't seized. The crank still worked, so I cleaned all of pine needles with a blow gun (compressed air). I removed the air filter and cleaned all the crap with the blow gun and gas in my nifty hair dye bottle which are my two favorite tools working in tandem. Once the intake side was relatively clean for a first start without the air filter, I used my hair die squirt bottle with 45:1 premix to get the engine running which it did within a couple cranks. When it quit after a few seconds, I gave a little more to start and drip fed the carb to keep the engine running for a minute or so. I still find it ridiculously easy to feed an engine gasoline while manually adjusting the air/fuel ratio by how much I squeeze the bottle.
For running the engine without an air filter, as long as it is not a windy day then I not squeamish about doing this. I have done more than my share of endless pulls which put a ridiculous amount of strain on my back that a little dust going into intake for a short period no longer bothers me.
Now that I know it does run, then I can put the time&effort to clean the deck, plastics and carburetor. The gas line was split and I had clear gasoline hose to replace it with. The hose for the primer was stiff, but it was still good enough. The carburetor bowl had junk/black premix gas, but nothing worrisome. I removed the float and needle was nice with no gunk and only needed light cleaning. I remove the screen filter from over the main jet then unscrewed the jet to blow brake cleaner through all of the passages and the MJ. I used my 7X magnifying glass to look through the MJ and it looked good to me. The primer line got cleaned-up the same way by backflushing through the carb passage and it came out clean. Keep in mind there was never any Ethanol in that mower, so this was straightforward cleaning.
Next I cleaned the gas tank having green slime. I kept a sample to show the owner, but didn't bother to take a picture. Surprisingly the gas cap was still venting. The thing is these caps have a somewhat open vent and do not hold the lighter ends of the gasoline, so the gas does not remain good for long. Keep the mower out of the sunlight and in a barn/shed that doesn't see temp swings, then the gas will be somewhat ok to run the next week, but it will have lost a lot of its potential. Keep it under a plastic car shelter and it probably won't start within less than a couple of week if not days.
Once the gas tank was cleaned, I tackled the female spade connectors from the On/Off switch to the ignition coil. I dipped both connectors into a glass jar that I filled with vinegar and table salt, then neutralized them with water and baking soda, blew dry them with the blow gun and applied dielectric grease.
Put it all back together, tested the primer which showed to work from the flow in the gas line intake that I had replaced with a clean hose. I pumped it several times to see if it was working, but too much gas is rarely an issue from my experience. I proved it enough times with small engines and sleds. With a carb or SDI, I have have shown how not enough gas to start can cause a spark plug to wet foul. Then I lightly clean the plug and give it lots of gas for a cold start. By the way, brake/carb cleaner with a tooth brush is enough to clean a relatively clean but otherwise wet fouled spark plug.
It started on the first pull and off I went to mow a couple slices with 40+ year old rusted blades. I found the engine was not turning fast enough, so I wondered about this plastic lever above that I had noted was connected to the governor with a light spring. I was surprised that it raised the engine rpm significantly.
A Lawnboy is not a mower that I am not familiar with other than having seen it being used since the mid 70s and kept seeing them being used for at least two decades until the four strokes took over. I still remember the mowing crew on the McGill University campus using them. This one Lawnboy had no handle, but rather ropes to guide it along the steepest incline and the guy was walking back and forth from the top. The first one I saw was in 74 when when my neighbour Ken had setup his father's self propelled Lawnboy with a couple of wooded sticks to move himself forward and backwards while crouched over the deck. It would become the earliest engineering marvel that I did see.
This was more for a challenge and for my own curiosity to see if I could get a push mower running after sitting a few decades. I would not have cared if it was a four stroke, but this was a vintage two stroke Lawnboy which to me is not too far from working on a vintage two stroke saw or sled.
