Hi everyone I guess I am looking for an opinion as to whether to rebuild or get new powerhead. It has been using oil for a while now but recently it started to run rough. Went to change out the plugs and discovered that 4 plugs were black and that the #6 plug also had rust on bottom. after starting it up, it still ran rough, disconnected the coil packs one at a time and found that only 2 made a difference. Not sure if I should rebuild it or replace it.