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-   -   Mercury seawater/fuel pump (https://www.offshoreonly.com/forums/general-q/164490-mercury-seawater-fuel-pump.html)

Viper TT 07-28-2007 02:48 PM

I just checked my pumps today and the port engine seawater pump was full of fuel! The starboard engine seawater pump also had a good bit of fuel in it.

What a crock! :throw:

ACTIVESHACK 07-29-2007 08:54 PM


Originally Posted by Viper TT (Post 2215107)
I just checked my pumps today and the port engine seawater pump was full of fuel! The starboard engine seawater pump also had a good bit of fuel in it.

What a crock! :throw:

A couple of my buddys have checked theres this weekend and all of them had gas in them :eek:

Cignificant 08-01-2007 08:00 AM


Originally Posted by Nordicflame (Post 2212976)
Maybe I'm one of the lucky ones ;)

Actually, I have done several upgrades with these setups and have always replaced the diaphram assembly with a Holley high volume diaphram assembly off of thier pump set up (note: you can not use the Holley armature assembly) Just remove the 6 (or 8, don't remember) and put in on in any rotation that fits your set up.
I have not had a failure or leakage on any of these. The old Merc/Carter stuff must not like the environment or like I said I may just be on of the lucky ones :)

Dave

Ditto, I've never had a problem...

michigan troll 08-01-2007 09:05 AM

In a similar note. I run the sea only and seperate electric fuel pump and mine burned the sea pump bearings up. They only have a minimal amount of grease on the shaft bearings. I purchased a new complete pump and drilled and tapped a hole at the centerline of the shaft and filled with gear lube. Bearing failure solved.

cloudmaster_321 08-01-2007 12:56 PM

how is gas and water getting into the oil?

Panic Button 08-22-2007 10:37 AM

Looking at the seawater pump mounted fuel pump, can someone explain how to remove the arm off the old pump and the diaphram. I have several new engine mounted Merc pumps and hate to drop $160/ea for 2 new pumps.

cosmic12 09-16-2007 09:49 AM

I just read all of this and just can't believe Merc gets away with it. For the price they get for them. I am now glad my 525 is gone.:(

theloanpro 05-03-2008 02:18 AM

Activeshack,

How long were you running the boat after losing the oil? Was that engine starving for fuel which lead you to discover you lost the oil and the ruined pump?

c_deezy 06-05-2012 04:08 AM

TTT for good info.

I pulled my raw-water pump/fuel pump off tonight to change the oil and check the impeller, I've got about 110 hours on this impeller.

When I loosened up the fill screw on the oil reservoir it practically shot out, it was so full of extra gas.

I typically only put about 55-60 hours a year on it, last year was a good year. Just going to have to check it more frequently from now on.

Raylar 06-05-2012 10:40 AM

As long as I have been exposed to this Mercury antiquated and somewhat stupid expensive mechanical fuel lift pump running off a very expensive proprietary Mercury water pump I have scratched my head and said:
Just remove the water pump/fuel pump, throw it away if bad, sell it if good and install a nice easy electrical low pressure efi type lift pump and connect it to the fuel pump relay and the inlet (tank feed) , connect it to the fuel line feeding the water seperator and install a standard inexpensive Bravo raw water pump on the bracket and BE DONE WITH THIS STUPID, EXPENSIVE, ANTIQUE SYSTEM! Come into the 21st Century!
There is no valid reason to stay with this expensive old system!

Best Regards,
Ray @ Raylar


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