Theoretical Question

[Nautical]

What's best guess on the life expectancy of mechanical lift pumps on Yamaha 4 strokes , and on the leathers ???

[rodbolt17]

dunno what a leather is.

I have seen the pumps go 15/20 years.
I have also seen them fail at 3 or 4.

[Nautical]

When I was younger we used leather diaphragms that we cut out of a piece of leather for our fuel pump diaphragms.. then rubber came along..then better rubber came along.. now I have no idea what they make them out of.. back in the day diaphragms were called leathers in terms of fuel pump discussions .

[rodbolt17]

back when we repaired the manual hand water pumps(well water) we called them leathers and they also had a frog.

most time the failures on the pump diaphrams I see are caused by deteriorated fuel eating the rubber.