Someone take the governor out? Happened to me on a riding mower that look like a race car. Man it was fast, power slide on grass, burn some rubber on asphalt. Then boom. I went from :I it was the best mower. Did the yards in minutes.
It’s a 4hp tecumseh. The one on my bike was purchased still on the crate as a mini bike/snow blower replacement. KID
When I was an auto repair instructor, we had an "exploratory" program that was designed to allow the students to see what was involved in each vocational program. I had the kids disassemble and reassemble small Briggs & Stratton one lungers. I then decided to get fancy and replace the flatheads with small overheads to be more representative of what the kids would actually be working on. The OHV Briggs was quite a bit more complex then the flatheads and one pair of students didn't reinstall the governor correctly. The students had been instructed to have me or one of the other shop teachers check the engine before they attempted to start it. Naturally they didn't; the engine went to about 8,000 rpm before it spit the connecting rod through the side of the block. The upside was that both students were covered with oil - we gave them shop coats, but they weren't wearing them. The rod broke, the crank was gouged beyond repair and there was a hole in the side of the block. I had the school welding shop weld the broken chunk of block back into place, and I bought a new crank and rod. We put the engine back together and used it elsewhere in our program for many years after the blowup.
