Once again, great advice! Thanks. The sequence of events was as follows.
1. I removed the scored piston/rings/conrod from the mower above.
2. I replacet the piston/conrod with donor parts, plus new rings.
Unfortunately, I didn't hone it - don't have a hone as yet. The mower has been used for about 15 mins max since putting in the new piston rings - most of that was unloaded running. It is too late for honing now? Have I damaged the new rings by not honing?
My main concern is that although it's working great, I have an older style (power torque) piston in a newer style block. The only difference is the position of the ring stops, but I'm not sure if it will affect the rings if the ring ends are in the wrong position. Perhaps they may contact with the newer style transfer ports? The Gregory's manual recommends not to use the older style piston in the newer style block (I didn't read that until AFTER replacing with the wrong piston) but the newer style piston can be retro-fitted into any 160cc engine. I did pick up another power torque with the newer piston. Unfortunately, it was scored even worse than the original one.
I contemplated wet/dry sanding it smooth but thought it was too far gone. The pics don't accurately show the damage. After reading about your experiences, I think I'll try to clean up the original piston and see what happens.
If I install new rings, what difference in performance can I expect from an engine that has been honed...or hasn't?
Regarding warranty, I could probably handle a 3 month period as you suggested. Is your warranty a "verbal" contract or do you have a written warranty contract? I can only imagine all the other sorts of silly things people return mowers to you for. It must make life interesting...well at least sometimes perhaps?
All your advice is greatly appreciated Rodeobob. Thanks again.
