I recently overhauled lister 8hp, I changed the element, nozzle, rings but since then have been having issue of misfiring, even the rpm is not normal, the engine raise and low it self, and I could hear sound of nozzle, I have adjusted the pump lifter but still the same.

And after that I adjusted the fuel pump tappet and I heard some noise inside the engine like Connecting rod stuff which make me think may be the spill timing is too advanced.

I opened the the engine, but nothing happen to the Connecting rod but I found abnormal thing on the camshaft gear, the pin they used to hold the gear has came off and also to gear hole is not aligned with camshaft they have changed the gear before.

And also please what could be the reason for crankshaft to be moving in and out.