165HP mercruiser I6. Set my idle mixture screws to get a smooth idle at 700 rpm. Set my timing to 6 deg BTDC and the engine seemed to run fine. I used a vacuum gauge to get the highest vacuum when setting the mixture screws and the needle was holding at about 15 to 16 Hg. which indicates "Late Ign. Timing" (according to what's printed on the gauge). So I advanced the timing, the gauge went up to 17" and seems to run smoother. I reved the engine up to 2000 rpms just for a few seconds to see if it would miss or ping but it was fine (I didn't want to rev it too long because I'm doing this in the driveway with the hose flush kit). Locked down the hold down bolt and called it good. But I'm worried it might be too advanced. My timing pointer is hard to read and I'm guessing I'm at 12 degrees, maybe 14 degrees BTDC. Attached is a pic of where the line on the crank is in relation to the pointer. Am I reading this wrong? Should I rely on the vacuum reading and leave it as is? Or change it back to specs of 6 BTDC? Thanks for any input.