125 hp fuel pump diaphragm

[erosenwinkel]

Just purchased a new fuel pump diaphragm for my 1985 125 hp Force (1258x5a) I have never replaced this part and simply wanted to know if there is anything I need to keep in mind before I do this replacement. It was cheap, it hasn't been changed in quite some time according to the previous owner so I figured I would make a pre-emptive strike. Thanks, Eric

 

[foodfisher]

Re: 125 hp fuel pump diaphragm

Pay attention to the parts as they come off, so you put them back in the right order. Something about the gasket.

 

[erosenwinkel]

Re: 125 hp fuel pump diaphragm

I did not purchase a gasket, just the diaphragm. Is a new gasket necessary? It would be nice to know before I open it up. Thanks.

 

[jerryjerry05]

Re: 125 hp fuel pump diaphragm

If the gasket is readily available,change it too.
The old might come off in pieces and might not re-seal.
I fixed a pump for a guy.He insisted no new washer.
It cost him about 80$ for return visits cause it would leak from a new spot evertime I fixed it again.
Finnaly put in a NEW gasket and problem solved.

 

[erosenwinkel]

Re: 125 hp fuel pump diaphragm

Awesome. Thanks for the reply. Eric

 

[BobList]

Re: 125 hp fuel pump diaphragm

I changed mine out without removing the pump, just the cover, and put the new diaphragm in. It was non directional, no way to screw it up

Bob

 

[bentle]

Re: 125 hp fuel pump diaphragm

If you don't already have one then it would be a good idea to install a small fuel filter between pump and carb.

 

[jiffyboat]

Re: 125 hp fuel pump diaphragm

a brand new pump is like $50 ...by the time you buy the diaphragm the gasket and still there is a spring inside that is good idea to change, and also the screen filter, you will be close to $50... I think is better to invest in a brand new already assembled ready to install .... by the way there is no way to change the diaphragm to this pump without removing it, BobList maybe just changed the filter screen wish is under the round cover,,that pump have six bolts and four of them pass trough out the diaphragm and hold the pump to the block if you don't remove those four, there is no way to change the diaphragm , and the other two bolts have two small nuts that never state in place when you take the bolts out

 

[erosenwinkel]

Re: 125 hp fuel pump diaphragm

Super simple just went to "huh" ? "other two bolts have two small nuts that never stay in place when you take the bolts out...... What does this mean? Kind of like going to the doctor and having him say "everything looks great, picture of health" and then as he walks away he says under his breath " see you in a day or so at your funeral". Not trying to be rude but what does this mean? I have never done this before and that is why I am asking for help. Thanks, Eric

 

[jiffyboat]

Re: 125 hp fuel pump diaphragm

is very simple Eric , but you need to take the pump out of the motor, remove the bolts and slowly open it , you don't want the spring that is inside flays away ... , but you will need the gasket that seals the diaphragm the the pump body , most of the times it brakes when you open the pump, now to assemble back insert the bolts back in the pump body and next the gasket or the diaphragm ..wish ever go first..you have to pay attention to it at the moment of disassembling, ...go idea is to take some pics...the reason of inserting the bolts is to align the gasket and the diaphragm to the holes... good luck

 

[BobList]

Re: 125 hp fuel pump diaphragm

Nope, did the diaphram.. the pump housing never came off the block.. it was stuck tight, I didn't pry it off.. i have an 88, the pics on boats.net shows the 85 might be slightly different, poor scan quality, can't be sure. The 4 bolts will remove the pump assembly, when you split the case after removing it the two bolts and nuts on the rearward side of the pump has the nuts that fall out.. to keep them in place when reassembling, I take a small piece of paper, lay it over the little hex shaped socket for the nut, and push the nuts into it.. it holds them good enough to start the bolts. If they get lost, they are a standard size, easy to find around the house, or hardware store.

88= http://www.boats.net/parts/search/Merc/Force/1988/H1251F88D/FUEL PUMP/parts.html
85= http://www.boats.net/parts/search/Merc/Force/1985/H1251X85A/FUEL PUMP AND REED PLATE/parts.html


Bob