Invader 22
My main site home allsorts *** *** Zinc & Inpellor

Buy the proper gasket for this end plate - the thickness is important to give the impellor the right tolerance - and polish up the end plate before replacing ( on the inside !! )
For Yanmar parts near Bristol, UK - T.E.Rollo - near to the entrance to Portbury Docks, just off the M5 Gordano junction. Very knowlegable, helpful and efficient ! That makes a change.
Changing the Zinc - 1GM10
For location see here.

Well - it's supposed to be easy isn't it ? - Firstly, my zinc was completely dissolved away leaving just the stub of the anode. Had I been at home I could have put it in the vice to free it ( next on list - small vice for boat ! ). Anyway, I found a spare stainless nut - so got my trusty minitool and sliced it.
I then see that the zinc is screwed into the plate as well. Washer was OK - would have thought I would get a new one with the zinc ! If you order a zinc, order a new washer. Yanmar prices are nuts ! Yanmar oil filter - 6.50 ukp (cheap) Yanmar paper gasket for this zinc plate - 5.60 ukp ! yet the head gasket is only 24.50 ukp !

Impellor - more problems.

I had the housing off - so could see well what was going on. ( I had drained the oil - the housing is low down on the crankase, so do not know if you would loose oil if you remove it without draining ).

When I looked at my new impellor - and the one I removed - there was a subtle difference ! My old one did not have a middle - just the rubber. Maybe in removing it I had prised it off, or it may have sheared off anyway. No matter, but, this old stub was not coming off this spindle.

I hate to imagine what a new housing would cost - it has a substantial bearing and seal at the back - big bucks.
So, out with the minitool, plus engraving point - very little clearance here - and gradually ( see middle ) grind away the offending bit. having duct taped up the rear bearing - my dentist would have been proud of it !

Then it's off - a quick clean up of the centre spindle and the new one slips on fine.
I'm glad I had the housing off - took me about a hour I suppose - with head scratching time included - inc coffee and a couple of cigarettes !