I bought one back in 2003 or 2004 and I mothballed the Homelite smoke machine. It didn't have the pure brute force of the 32cc machine, but it had torque. Something I wasn't used to at in a weed whacker. I was so impressed I bought the "tiller" attachment. Unfortunately, I didn't take proper care of it and the engine seized.I just bought a 4cycle weed whacker........... somebitch is heavy. Quiet but heavy!
Fast forward to 2016, when I first started at Ace, I bought another that we couldn't get to run straight out of the box. We got credit for it from Crapsman and it sat around for parts. One day we were cleaning up and it was offered to me. I brought it home, bought a replacement carburetor, and I was still fought to keep it running. I found out that the valves were out of adjustment from the factory in addition to the carb being crap.
I initially used the 4-stroke to keep the growth down on my neighbor's waterfront riprap, but discovered the boom on the Homelite was longer and machine was better balanced , so it caused less back fatigue. If you use good fuel and stabilizer in your 4-stroke, and one day it just won't start no matter what, check the valve clearance. Factory specs are .002" and .004" and that doesn't leave much room for error. They're slightly forgiving, but they need to be at least close. My Crapsman wasn't.
While finding this video, I also ran across one for "non-adjustable" jets on the carburetors these 4-strokes use. The guy is a bit of a jerk, but who isn't? I'll post an update here after I personally test this theory.