I need some help on an old LT 185 (84 model I believe). I just put new rings in it and got it all together and cant seem to get the decompression valve in right or to operate correctly. It has a flat spot on the end of the shaft that seems like it has to be insalled at a certain timing point. I would greatly appreciate any help on the matter. Thx in advance.

 

Any ideas? Really appreciate any help. Thx.