Still trying to find a manual. Google has failed me so far. When I bought the boat the engineer at the marina said it was 'silicone' that you need to feed it every 200 hours, another engineer at another marina mentioned the same.
I did find this thread:
It hasn't leaked at all so far, so I guess it's not urgent but I have been getting a rubbing sound on the prop shaft (best way I can describe it). Might just be something on the prop so I'll do a dive on the weed hatch tomorrow. The boat will be out for blacking in October so while you are supposed to be able to lubricate it in the water, maybe it would be best to wait and have it all apart then.