I might have screwed this Lawn Chief repair up. But, it worked out in the end.
Preface
I bought this machine for the wheels and hubs. At the time, I was working on a Cub Cadet that had three bad tires.
This machine was cheap enough, so I thought perhaps I could just swap these wheels on to that machine, but the hub style was wrong.
And so it sat.
A couple of weeks back, I was going through my stash of machines to figure out a priority schedule for getting things out the door before winter.
I did a simple compression test to determine whether it would be a relatively quick repair so I could get as many machines fixed.
This Lawn Chief had surprisingly good compression. Since it had no deck, I figured that I could sell it as a pulling machine, plus I wouldn’t have to worry about repairs to the deck.
Just get the engine running and ensure that the transmission works. Simple, right?
Diving into the Repairs
Turns out, it wasn’t that simple. As I was starting to shoot the video, I had the jumper pack on the battery leads to turn the engine over. Here is where something interesting happened.
It seemed as though extensive compression had built up because the jumper pack could not spin the machine over. It would get to a certain point, and the starter would just give out.
At this point, I fell victim to the internet diagnosing. I couldn’t figure what could be causing this, so I did some research.
The two probable causes were: an improper valve gap and a sheared decompression valve on the camshaft.
I checked the valve gap, and it was off by a little bit. So I set it within spec, but the problem persisted. At this point, I was certain that it was the decompression valve.
I watched the push rods, and it seemed to indicate that the decompression valve was functioning. That being said, the movement is very small, and I wasn’t sure.
The only way to confirm was to open up the engine and visually inspect it.
So That’s What I Did
Unfortunately, nothing really stood out. The decompression valve was intact. I did find a few interesting things on the inside, however.
The valve guides were incredibly tight. The valves did not travel very well, and it took quite a bit of polishing of the valves for them to slide unencumbered.
Also, the cylinder wall had two small protrusions on the surface. I thought that perhaps that could restrict the passage of the piston, but it appeared as though they were beneath the piston skirt, so there should have been no contact.
Having discovered nothing of real significance, I simply cleaned everything, honed the cylinder, and ground the valves.
Once that was complete, I put it all back together and finished the machine. I did have to purchase a new gasket set to account for the gaskets ruined during the deconstruction.
A Possible Diagnosis
The point where I think that this was all unnecessary is this theory:
It’s possible, and I can’t confirm it at this point, but I think perhaps the jumper pack was just low on voltage.
It doesn’t make sense that it spun over for the compression test, but it wouldn’t turn over afterward. Nothing else had changed.
It wasn’t hydrolocked, the valve gap was relatively close to spec, and the decompression valve was working.
If the jumper pack was low, perhaps it didn’t have enough juice to turn over, and then I went down the rabbit hole of chasing a problem that didn’t really exist.
That being said, the valves were tight in the guides, so maybe that was the issue. I don’t know. At the end of the day, I gave the engine a good cleaning, and a proper overhaul can’t be a bad thing, right?
All it really cost me was around $30 for gaskets and some extra time. The resultant experience is far more valuable.
Watch for yourself, and let me know what you think.
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