lower unit not excepting lube
To refill the gear case;
With the outboard in the vertical position, add lubricant until it appears in the front vent hole and install the plug with sealing washer. Continue adding lubricant until it appears in the rear vent hole. Stop adding lube and install the rear vent plug and sealing washer before removing the fill tube. Remove tube and replace the fill plug and sealing washer. My Owners Manual does not mention the two vent plugs, so I was trying to refill the way I did with all my older Mercurys that had only one vent plug.
As far as filling slow, don't we all use a hand pump? You really can't fill too fast...