1989 85 hp force fuel pump ?????????

I'm a newbie to outboards but learning everyday, heres my new question.
I bought a fuel pump off Ebay and put a new diaphram in it and put it on my motor.
After I took the orginal fuel pump off and opened it up I noticed that the valve/plunger in the bigger hole was sticking out and would compress if i pushed on it. The fuel pump that I put the diaphram on didn't do this. Not sure whats going on.
Is the pump with plunger sticking out good or is the pump with the plunger that didn't stick out good? Or does it matter?
Not sure if my description of the parts and whats going on makes sense but this is the best I can describe with my now-limited knowledge.
If you can help me please do. I can clear anything out that you might not understand what I'm trying to say. Thank You

Re: 1989 85 hp force fuel pump ?????????

Pictures say a lot more.

Re: 1989 85 hp force fuel pump ?????????

here is a link with the pic diagram of that pump, just tell as wish part #

http://www.boats.net/parts/search/Merc/Force/1989/H0853K89B/FUEL PUMP/parts.html

Re: 1989 85 hp force fuel pump ?????????

The fuel pumps work by having the diaphragm under alternating vacuum and pressure from the crankcase. Earlier fuel pumps did not have the spring loaded "plunger." Later pumps had this installed behind the diaphragm to help equalize pressure between vacuum and pressure pulses, thus slightly improving fuel flow.

In reality, it doesn't matter which pump you use. As long as there is a new gasket and diaphragm installed it will deliver enough fuel.

You do, however, need to be careful as there were several pump designs: One type was integral with the bypass cover and another bolted on top of the cover with a gasket between them. They are not interchangeable unless you also change the bypass cover. Then, of course, there was also the Mercury style square pump.

Re: 1989 85 hp force fuel pump ?????????

Thanks Frank, Both pumps look the the same on the outside and also under the screen filter cover, so I should have the correct design just an earlier pump. I THINK!!