Volvo Penta MS25S 2.47 "gear ratio" with 130S

[Rumble]

I have tried to source this question on the net, and various manuals including the MS25S workshop manual. The manual includes both the upper housing and lower housing (incorporating the sail drive), with total gearing designated at 1:2.47.


There are two gearing units. The upper gearing houses the gearbox with different size gears, the larger being on the vertical shaft (32 teeth), and the lower leg comprising gearing cog sizes that are also different, the cog on the propellor shaft being the larger one with 24 teeth.


In short, does anyone know off hand what the separate ratios for each gear in both the upper and lower housing units are?


...this'll save me dismantling the MS25S and physically counting and comparing revolutions when the boat is next on the hard.


Counting the number of teeth on cogs method does'nt arrive at 2:47 either, so I am guessing different shaft sizes could be the reason for this (upper 24/32, lower 16/24).


Thanks to anyone in advance who can help!