Wanted to share the process I followed including weighing the grease at multiple stages to get the exact measurement of what I pumped into the bearing housing. Being an engineer I like checking myself through more than one method and that's what I did this time as well.
Phase 1 - Calibrating equipment. I picked a plastic measuring cup from some old medicine I found in the house that had clear marking of 30 ml (1 oz). I measured empty cup on scales - 5 g. Then I filled up the cup from my grease gun up the mark and counted number of pumps it took. New weight - 32 g over 25 pumps.
Before pumping I weighed loaded grease gun - 1619 g. Weight after pumping out 30 ml - 1593 g.
Conclusions
1) cup gained 27 g of grease
2) gun shed 26 g of grease
3) ratio of grams to pumps is 1.08
4) experimental density of the grease turned out to be 0.9 g/ml. This checks with theoretical specific gravity of marine grease I found on the Internet as .895
Now I could calculate my target weight limits for filling the bearing housing
low limit 1.11 oz - 30 g
high limit 1.18 oz - 32 g
Phase 2 - Pumping grease My first attempt at pumping grease was unsuccessful. I made bad connection with a grease nipple so ended up spilling the grease without getting any of it in. Still I was able to confirm that none of the grease actually made it in. Here is how. Gun starting weight - 1590 g, end weight - 1580 g essentially transferring 10 g over 10 pumps.
I wiped off all the spilled grease with a towel and measured the towel before and after. Dry towel weight - 22 g, after absorbing all the grease - 31 g thus accumulating 9 g of grease total
Learning from this lesson I made a good nipple connection and had 4 subsequent successful pumping sessions.
session #1 start weight - 1581 g, end weight - 1576 g, delta - 5 g, 5 pumps
session #2 start weight - 1576 g, end weight - 1565 g, delta - 11 g, 10 pumps
session #3 start weight - 1565 g, end weight - 1554 g, delta - 11 g, 10 pumps
session #4 start weight - 1554 g, end weight - 1549 g, delta - 5 g, 4 pumps
Conclusions
1) I put in exactly 32 g of grease, i.e., right at my upper bound
2) It took 29 pumps confirming my theory of relatively constant gram to pump ration of 1.10
3) I could have done everything by counting pumps alone but I would not be so sure of the final outcome
Any feedback is appreciated. I also used a very similar methodology for changing the oil without worrying about overfilling. Ping me if interested.