12 hp kohler issues

[wj-ihc]

Hello, new member here, glad to be part of the group. This past summer/fall I have been working on restoring a 123. I found a worn out 10 horse block, had it bored to a stock 12, had my crank ground 10 under, new rod, had the valves done, starter/generator rebuilt, new coil, points, condensor, wires, etc. Rebuilt the carb. The engine would fire up pretty well but runs horrible off of an idle. It will cut out and act like it just won't go, like it isn't getting fuel. It also seems to idle very rough. The whole tractor just sort of shimmys when it is idling, like it is out of balance a little, worse than what I would expect. I checked to make sure I was getting good fuel flow out of the tank, took the carb back apart, even tried a different carb of a runner, same results. Started looking at timing, hooked a light up to it and varied the gap, this would change the way it ran, but would not completely correct it across the rpm range. On that note, I did not find an S on my flywheel, just a single casted line that passes the sight hole. This line seemed to approximately correspond to the timing light?? I tried differnt points, coils, condensors, plugs, unhooked generator, nothing helps it. Finally had time to pull the engine out of the tractor this weekend and pulled the pan to check timing, line on the crank matches perfectly to dot on cam. Valves are set correctly. I am at a lose at this point. Only thing I can think of is possibly a valve not seating right or haning up in a guide, the ACR sticking, or the lobe on the cam for the points pushrod being worn or the rod its self. Any help on this would be greatly appreciated. I have a short video I took this summer of the engine running if anyone would like to hear it. Thanks.