That is correct. The lower two screws are just loosened and the upper
two are removed. Then the plate just lifts up and off. I didn't have this
system on my Yanmar (3GM30F) and never changed an impeller on it
so I can't comment on that part. Its got to be better than trying to use a
screwdriver or nutdriver around a blind corner though.

Doug
s/v Callista

"Hmseconomy" wrote in message
...
Especialy good on the Yanmar reverse facing pumps. Can replace the
impeller by feel. BRBR

I've got the Yanmar 2GM20F with the waterpump facing aft. It would appear
that
this model for require the SpeedSeal with four thumbscrews. Is that
correct?
If so, it also seems that two of the four would remain in place as you
slide
the cover into their slots and then put in the last two thumbscrews. How
difficult is that to do by feel as you would not be able to see the screw
holes?