Made a 16 mile round trip today and on the way back my engine started running like I had cruise control......it would maintain 30mph with very little throttle, I thought yep air leak, maybe carb gasket or crank seal gave it up, I got it home and thought about the fact that my carb hadn't been acting right either so I rejetted another NT I had and put in on the engine and then desided to take it for a quick spin to see if the other problem got any better or not because it did idle a bit better, but after about 50 yards it was trying to take off on it's own so I knew I hadn't fixed a thing.
I pulled the mag cover off and seen the problem real quick, metal shaving all in the cover and on everything else, the mag rotor had eat into the block about 1/16" deep and ruined the crank seal, I held the rotor with some pliers and pushed and pulled on it and I have about 1/16" - 3/32" end play in the crankshaft, so it looks like this block is toast.
dang it this was a super good running engine and only had 402 miles on it, I had shaved the head and done some pretty good porting on this engine, it was a very strong running motor, not sure what gave way internally, I will know once I get into it later...
I have a spare 66cc slant that has real nice clean ports with no mods to it yet, I'm gonna mount it up and start the break in proccess and hope it hold up longer than this last engine.
Like I always say about these 2 smokers.......they're all a crap shoot, you just never know.....that just part of it and the price we pay for such an inexpensive hobby to get into, quality is something we may get from time to time but not all the time for sure with these cheap china made engines.
wish me good luck on this new engine... I'll post some pics here shortly showing what I found in the engine under the mag cover.