Yanmar 2gm20f

Oct 29, 2017
88
ODay 302 Kenosha WI
1. Has anyone replaced stem seal without removing the head on a Yanmar 2gm20f. Is it reasonable possible? My repeatable diesel mechanic where I get my Yanmar part thinks it is if you are at TDC when replacingthey don’t work on marina engines but have done it a vehicles.

2. My Yanmar 2gm20f has the cast hole on the clutch housing for matching mark. I have the manual hand crank and turn the handle until it gets tight, check for matching mark with no luck, continue to inch along, still can not find it. Did this about a dozen times. Any suggestions, I am expecting to see a 1T and 180 degrees out a 2T. Am I missing something?

thanks