I recently purchased a used buggy for my sons to use. Before letting them tear off with it I replaced all the oil and adjusted the idle as it was too high to change gears without tapping the kill switch to lower rpm. They put it through a good workout for several hours, I noticed a little smoke and the smell of burning rubber. After it cooled down, I couldn’t find any wires that looked burned. On the next outing it sounded good initially, but top end was not the same. It eventually started smoking bad and pinging. Little metal flakes were coming out of the plastic opening on the transmission I believe.. on top of the engine/tranny, not exhaust. I shut the unit down and later started it to get it back on the trailer, but now it would not engage into gear either. Is it shot, or worth fixing. My initial inclination is it’s a replacement.
It sounds like there is a combination of issues going on internally. At a glance, I would say replacement is the best option if you're looking to avoid the hassle of diagnosing and rebuilding.
If you're mechanically inclined and interested in rebuilding instead of replacing, upload some pictures showing the areas of damage/flakes/problems so I have a better idea what you're dealing with.
To outright replace the engine, here is our solution which comes in less expensive than an OEM replacement:
150cc to 175cc Replacements (All of the engines listed will fit with the compatibility kit below)
Compatibility Kit Type 6
https://www.buggydepot.com/product/663/ ... odels.html