Changing the diaphram of the fuel pump

capslock118

Petty Officer 1st Class
Joined
Apr 27, 2009
Messages
249
Hi there,

I spoke with my mercury dealer for fuel/water seperator recomendations and he mentioned that for the age of my engine I should replace the diaphram in my fuel pump.

Engine: 1990 135hp black max 2-stroke v6.

The assembly diagram on the mercury website does not make the part fuel pump overly complex to take apart and fix, however...

Is there anything I should look out for when taking the fuel pump part and replacing the diaphram? I am a novice in engine repair at best; i replace spark plugs and in-line fuel fitlers fine and I know how to use tools.

I figure it's just a matter of taking out the fuel pump, disassemling and reassembling in the same order i found the part.

thoughts?
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: Changing the diaphram of the fuel pump

Correct... The diaphram kit comes with instruction. One thing I would recommend. when you buy the kit, get half a dozen of the special cable ties used on the fuel lines. They look like normal ties, but if you look closely you'll see the difference. If the dealer doesn't have any, ask him what he's using. If he says just normal ties, find another dealer!!

Here's a photo of the special ties. Part # 54-816311T (they are 20c in your country, in Oz they charge $2 ea. :eek::eek::eek:)

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capslock118

Petty Officer 1st Class
Joined
Apr 27, 2009
Messages
249
Re: Changing the diaphram of the fuel pump

Good to know about the ties, when I replaced my in-line fuel filter i just used regular black zip-ties; they looked similar to what you are showing my except the ends.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: Changing the diaphram of the fuel pump

... i just used regular black zip-ties; they looked similar to what you are showing my except the ends.

That's the difference, and that is all it needs for the lines to leak.... Diaphrams are an annual service item....

Chris.......
 

capslock118

Petty Officer 1st Class
Joined
Apr 27, 2009
Messages
249
Re: Changing the diaphram of the fuel pump

Diaphrams are an annual service item....

That's an interesting statment. I've never heard of a diaphram needing to be replaced for the last 15 years ive been using boats. I've never gone down to the mechanical level of summerizing a boat until i've owned my own though so maybe this is why i've never heard of it being replaced.

the annual maintenance list seems to keep growing outside the list i've used and what seloc has mentioned haha.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: Changing the diaphram of the fuel pump

It's due to the wider use of blended fuels. The ethanol attacks the rubber. At$10, it's no big deal to do them, but at several thousand to fix a blown powerhead because the diagrams caused it to run lean.... which one you prefer??? :D :D :D

Chris......
 

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,589
Re: Changing the diaphram of the fuel pump

You can also get the ties from a OMC/BOMB dealer, part #320107
 
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