Re: 1976 evinrude 85 hphow does the fuel pump work?
Note also that on these models, the pulse that drives the pump does not come from the hole in the back, rather it comes from one of the three hose connections (the one at the back of the pump, if memory serves). Also, tread lightly when deciding to re-build the fuel pump. The pump on that motor was not designed to be serviced (although rebuild kits are available), only replaced. Make sure you keep track how the pump is assembled, inside there are two small leaf valves, two plastic caps with springs, the diaphragm, and gaskets. Everything has to go back in the right order and in the correct configuration in order for the pump to work correctly, and that can be tricky (especially the caps, they need to be just right, or else the diaphragm is stretched out incorrectly and the pump won't pump). Additionally, since they were not meant to be rebuilt, the gaskets are pretty well adhered to the different plates on the pump, so you have to carefully work them off. The upshot is that if you do need to service the fuel pump, and you are successful in rebuilding rather than replacing, you can save yourself about $70. I had a previous thread about rebuilding the fuel pump on my 70 HP Johnson, and someone was kind enough to provide a diagram that roughly corresponds to your fuel pump. This along with pictures I took during disassembly were invaluable in correctly re-assembling my rebuilt fuel pump.
Good luck!
Rgds
