Setting GM Hydraulic Lifters

Hi all; Shortly I will be doing this on a Mercruiser 140 (GM 181 CI Block). I just want to see if I have understood the process correctly, when the lifter is on the lowest part of the cam you back off the adjusting nut until the push rod can be turned freely then tighten just until the push rod resists turning, then 3/4 of a turn more. What I am wondering about is when you are backing off the adjusting nut is the spring in the lifter providing the pressure to keep the push rod from turning? Then when continuing to back off the adjusting nut until the push rod can be turned, has the piston in the lifter then reached the retaining ring in the lifter?

Thanks for any clarification on this, Jack

Hey Jack. Yes, the lifter spring's tension on one end and the valve spring's tension on the other end of the pushrod provide this resistance-pressure. I don't know about your marine engine, but we local car jocks save that extra 3/4 turn to adjust the click out of each lifter AFTER it is hot & running. We do as you said thru " then tighten just until the push rod resists turning", and this is NOT a great deal of resistance, just enough to barely feel.. That's close enough to start the engine. Then with the engine warm and a lifter clicking, tighten until it b-a-r-e-l-y quietens, then tighten an extra 3/4 turn. **Marines may differ.** And luck to you. Your understanding of the theory surely seems sound. s (It really sounded sound, but that didn't sound right; & Dan would've slapped my wrist for using such grammar--rightfully so, I must add!)