Re: 1959 johnson sea horse 35hp
Do you mean the plate held with two screws Just above the cavitation plate. Take this plate off, use it as a pattern to cut one out of sheet metal. Soft solder on a female hose connector with a hole through the sheet metal plate. I have made several of these over the year's. It will supply plenty of water, and it won't fall off, or get out of place when your back it turned like I've had muff's do many times. This plate does not have to be water tight around the edge's, and can leak water like a basket, and still supply plenty of water. You can probably make it for a dollar, or less. I have posted this several time's before in answer to this question. Each time someone came right back with you can get a snap on Perko for $20-$30 on Ebay. I once worked at a business that sold those thing's, but we never used them.