The thicker oil seems to increase the space between the
clutch plates. That’s my guess anyway. I checked the torque
to turn the prop when I changing the from gear oil to the
40W there was only an increase of about 10 lbs.
I don’t have an ARGI around here. The farm stores around
me don’t have a 40W except Tractor Supply but they only
sell it in 2 gallon jugs.
The number (Say 40) is the viscosity of
the oil. We needed to maintain it in some
of the coatings we ran using a Zhan cup.
I believe the weight of oil is (or was in the
beginning) measured the same the same
way. You time how long it would take for
the cup to empty. Using the same number
cup, 30W oil would take 30 seconds, 40W
oil will take 40 seconds, and so on. Multi
grade oils would be checked at different
temperatures.
A member sent me some of this.
A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.