Black Jack burning oil.

[SYMbionic Duo]

Idle seems fine, but as soon as i give it throttle, i get smoke. If i continue to let the smoke out, i start misfiring pretty badly.

Rings looked ok, but i didn't measure the their gap.

Very light scoring in the corners along the studs. (will have to remember to let the engine warm up first, before laying the hammer down.)

I just changed the oil with a different oil that's lighter weight than the 15w40 that the manual says.

Is it likely that that is the problem? or should i investigate the rings more?

[Christophers]

Idle seems fine, but as soon as i give it throttle, i get smoke. If i continue to let the smoke out, i start misfiring pretty badly.

Rings looked ok, but i didn't measure the their gap.

Very light scoring in the corners along the studs. (will have to remember to let the engine warm up first, before laying the hammer down.)

I just changed the oil with a different oil that's lighter weight than the 15w40 that the manual says.

Is it likely that that is the problem? or should i investigate the rings more?

My guess is the valves... only because this is what the problem was for me when something similar happened to me. YMMV.