Yanmar impellor

[VicS]

OK

You have presumably read this

The seawater pump turns in the
counterclockwise direction, but the
impeller must be installed by turning
in the clockwise direction. If the
impeller has been removed for any
reason and must be reassembled, be
very careful not to make a mistake
and turn it in the wrong direction.
Additionally, if the engine is being
turned manually, be careful to turn it
in the correct direction. Incorrect
turning will twist the impeller and
damage it​

in the owners manual.

That seems clear enough but totally illogical "

The workshop manual gives no guidance but includes this diagram which indicates that the pump actually turns clockwise

View attachment 72555

I guess I could find a diagram of the gearing to work out which way the pump really does turn but the easiest way will be to turn the engine by hand in its normal direction and watch to see which way the pump turns.

I'd suggest you then install the impeller by turning it the same way ............ Maybe someone will know better ?

And just to add to the confusion in the same manual as the above diagram I have in fact found a diagram of the gearing which shows that the pump turns counterclockwise !

https://www.manualslib.com/manual/740012/Yanmar-4jh3-Te.html?page=46#manual

Back to the advice I gave in #2, and which others have repeated, .... not to worry, just let the vanes sort themselves out!