What to lubricate rubber impeller with?

[ghostlymoron]

At one point in the rotation there is less bending pressure due to the shape of the body
At that point it will flick over to the correct angle. That is assuming it is a decent impellor & not an old one where the material has started to perish & gone stiff, or been stored distorted. If so it is ready to crack & break
I suspect It would not pump properly bent the wrong way
I suggest that people who think the lubrication stays on the vanes may be mistaking lubricant for the sludge that collects on the vanes from the water. This is more obvious when the engine has been left unoperated for a while.
I do not lubricate mine but have noticed this " sludge", for want of a better word, at the end of the season

Several contributers have reported one of the blades inverted when they removed the cover.

 

[sailorman]

Several contributers have reported one of the blades inverted when they removed the cover.

that might be because the piston hit tdc on stopping & bounced back on the stroke

 

[Jim@sea]

What about Brake Fluid. That is supposed to be good for rubber. After all wheel cylinder rubbers are soaked in it all the time, and under pressure.

 

[youen]

Today I change my impeller on a Volvo 2030 and the new impeller come in a box with a paper gasket and a small bottle of glycerine