How To: Rebuilding Merc Sea/Fuel Pump
 

Seeing that there have been a few recent threads on the Merc Sea/Fuel pumps I thought I would share the rebuild of mine. And the seals and bearing that I used. I am not a professional so don't flame me to much.
For the record I use electric fuel pumps and just cap these off, but I found out the hard way that they still need maintenance. If I could find an inexpensive HI Performance pump I might switch back to mechanical.

1. I used an Arbor press at work and pressed off the pulley. Make sure you put 1/4" spacers under the pulley so you do not bend it. You need to put the pressure on the inner part of the pulley.
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2. I took a screw driver and punched into the seal and pried it out.
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3. I removed the expansion clip.
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4. I knocked out the shaft: supporting the housing with wood and hitting the shaft with a hammer and a piece of wood in between. The front bearing will come out with the shaft.
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5. I used a punch and knocked the inside bearing into fuel pump cavity. You can wiggle the bearing out through the cam arm opening or gently knock it through the front bearing area.
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6. I then used a socket and extension and knocked the 2 smaller seals out that are between the inner bearing and impeller. They use 2 seals: one to keep the oil in and one to keep the water out.

Parts These are the bearings and seals that I used. At my bearing supply shop using micrometers we came up with a Metric bearing. :eek:
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Assembly Sorry not to many pics. Posting this was an after thought.

1. I put the shaft into the freezer to shrink it so I could get the bearings on easier. I greased the inside and outside of the bearings. Once cold I rested the bearings (6204-2RS/C3 $13.90ea) on wood and then the hammered the shaft through the bearings, using wood in between shaft and hammer. One bearing on each side of the shaft.

2. I then put the 2 smaller seals (CR-7464 $4.95ea) in backside of the housing 1 facing the opposite way than the other.

3. I then hammered both bearings through the front bearing opening. Don't forget to put some grease in the housing.

4. I put the expansion clip back on. (sorry blurry pic)
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5. Finally I put the front seal (7690 $7.85ea) over the shaft and seated it in the housing.

Nice I am sure a lot of guys will be glad to have this!

Very nice :drink:

Only one question
"I put the shaft into the freezer to shrink it"

I thought cold made things expand and get bigger :eek:

Nice job, thanks for taking the time. Those part numbers will come in real handy too :drink:

That sentence read alone is definitely not PG. :eek:

I hope you are just kidding. When you machine steel you can not get an accurate measurement until the steel is at ambient temperature. Heat expands, cold shrinks. :drink:

I will post my How To: Making a Plexiglass hatch later today. I posted it in the Scarab forum and I'll try to move it over here.

Great thread rookie. I'm just finishing up my pump rebuild also. Did the same thing as you, got the bearings and seals aftermarket thru a bearing supplier.

The only thing that expands, that I know of, in the cold is water/ice. Everything else shrinks.

Thanks for the help! Just used this pictorial to rebuild my sea pump for $32 after tax and overnight shipping.

I also added a valve to the bottom of the housing to drain the oil and check for water intrusion.

Did you use the Merc seal part # 13 and 19. The 2 Merc inner seals (26-90562) work better than the SKF 7464?

http://www.mercruiserparts.com/Show_...%28DESIGN+I%29