Has anyone ever done a full rebuild on their sea water pump with fuel pump?

I replaced my starboard mechanical fuel pump last summer in July. Boat would run great until I shut it off then when went to start again it would run for a minute or so then die and not start up again until it basically cooled all the way down. Sounds like Vapor Lock right? That’s what I thought too and what I actually found was that the fuel filter was about half empty when this would happen. I can take the fuel filter off the port motor (full) and would start up and same thing, die and spin the filter off and it would be half empty again. I ended up replacing the mechanical fuel pump and didn’t have a problem again, problem solved right? September…same exact problem. I was able to get the fuel pump warrantied out but not in time to winterize and put away for the year (North Idaho).

Now talking to some mutual friends and people all winter someone who knows someone had a problem with going through multiple fuel pumps until they rebuilt their sea water pump and have not had a problem for 7 years now. Problem is he can’t find in his records where he got the kit.

Now, did I just get a bad fuel pump and I won’t have a problem again orrrr is this going to be a ongoing repeating problem? I really don’t want to deal with that! I have been searching everywhere for a build kit and all I can find is the whole assembly replacement or just the shaft kit, part# 818366A

So back to my original question, has anyone ever done this or known someone that has?

There easy enough to rebuild with a press. Don't see the need for rebuilt unless bearings, seals or cam shaft is damaged

The gear lube needs to be checked/refilled every year to see if pump starts leaking gas

With it not pumping check your antisiphon valve on the tank, probably clogged or stuck

Rebuild thread

Thank you, Someone else had also suggested the anti siphon valve. I followed the line from the tank to the fuel pump and it appears to me that there isn’t a valve? The boat is a 2005 353 fastech. Maybe its in the tank? Or maybe I need to take the line off the tank and it will be right there?

Also my thought was is that the cam/shaft lobe was worn down that it is making the fuel pump work extra hard causing it to fail?

The boat is new to me, I got it with lots of records and looking through them I don’t see where anything has been done with the fuel pump previously. However, I can tell by the paint missing off the bolts that it has been off before so have to assume the oil in it has been changed previously.

Thanks for the Reply

And no I have never seen a sad person hauling ass lol Scared, but not sad!!!

While you have the fuel pump off drill and tap the bottom 1/8 npt and put a plug in it for drainage.

"usually" the anti siphon valve would be right at the tank where the fuel line going tot he motor connects to it. Looks like an oversized barb fitting but with a longer body as that's where the spring/ball assembly is inside.

What about the electric fuel pump in the cool fuel? I had an issue similar to yours and ended up changing it. Problem solved. 2005 vintage 525s also.

Thank you, I took another look and it appears i do have anti-siphon valves. I will get a couple ordered.

I did also remove the port fuel pump to change the oil and check duration and it appears that they are the same. (Without disassembling of course)

Still wondering if I should rebuild anyway?

Personally I would not rebuild it. I had one that blew out the seals and exchanged it plus $$ for a rebuilt. Lasted one season and blew seals again. It was replaced under warranty, and got my old one back rebuilt. It made it about 20 hours, before seals let go again. Replaced with a new Merc one and it has 2 seasons /100ish hours on it. My 25 year old Merc one on the other engine is still going strong.