I've a (new to me) 1976 Mercury 850 Outboard. I think I need to rebuild the fuel pump. There is an electric primer pump. I emptied the top carbs bowl by removing the brass jet on the front. Turned on the primer pump. The bowl filled with gas. I did not turn the engine over. Is this good or bad? If I do need to rebuild, how to I get to it? All the manual says is "remove....". It doesn't say how.