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Merc block mounted fuel/water punp: rebuild or new?

HitIt

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I have an older 454 Mag (Gen V) that has the block mounted seawater/fuel pump. The seal in the fuel pump went out last year and let fuel into the little oil reservoir on the water pump. Sounds like the bearings are shot in the water pump.

Should I rebuild it? How hard is it? If not, can I buy a rebuilt with a core charge? New seems to be around $400+.

It is one of these:
images.jpg

Every time I fuck with this thing it pisses me off. Fuel, oil, and water, all in one tennis ball sized part.... Really merc?
 

28Eliminator

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BAM marine has all the bearings and seals to rebuild it. I did mine a couple years ago. Seems it was about $100.
 

HitIt

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Looks like all I need is a puller for the pulley. Does that seem right? Are there bearings pressed on to the shaft?
 

28Eliminator

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Looks like all I need is a puller for the pulley. Does that seem right? Are there bearings pressed on to the shaft?
If I remember right, the 2 bearings pressed in from the outside of the housing. There was sequence of putting everything in that you had to pay attention to.. wasn't very difficult. I think the whole process only took a few minutes.

You'll definitely need a puller.
 

HitIt

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Got it. Going to pull it tonight. Thanks.
 

HitIt

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Got the pump off and I am going to rebuild it. In case anyone in the future references this post, the parts required are:

2x 26-90562
2x 30-72961
1x 26-806930

I also found the rebuild procedure and have attached it. The procedure calls for Loctite 514 (which is discontinued and has been superseded by 518) and Mercury Special Lubricant 101 (which has been superseded by 2-4-C). You will also need a power steering pulley puller like this one:
https://www.amazon.com/gp/product/B000CMFK10

The entire pump assembly part number is: 46-807151A8 and the housing assembly with the bearings seals is 818367A1.
 

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bsand

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Got the pump off and I am going to rebuild it. In case anyone in the future references this post, the parts required are:

2x 26-90562
2x 30-72961
1x 26-806930

I also found the rebuild procedure and have attached it. The procedure calls for Loctite 514 (which is discontinued and has been superseded by 518) and Mercury Special Lubricant 101 (which has been superseded by 2-4-C). You will also need a power steering pulley puller like this one:
https://www.amazon.com/gp/product/B000CMFK10

The entire pump assembly part number is: 46-807151A8 and the housing assembly with the bearings seals is 818367A1.
Reviving an old post..... @HitIt thanks for the info as listed above! I ordered part numbers as you itemized, to rebuild the pump on my 525. Thanks for doing the legwork, the rebuilt went smooth.
 

HitIt

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Don't forget to change the oil in the damn thing often. I just did mine and of course there was plenty of fuel mixed with the oil. Mine didn't have a drain in it like the new one so I drilled and tapped it to make the fluid changes way easier. It's only a couple ounces of outdrive gear oil but is a huge pain in the ass if you don't have the drain in the assembly.
 

H8Plow

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Don't forget to change the oil in the damn thing often. I just did mine and of course there was plenty of fuel mixed with the oil. Mine didn't have a drain in it like the new one so I drilled and tapped it to make the fluid changes way easier. It's only a couple ounces of outdrive gear oil but is a huge pain in the ass if you don't have the drain in the assembly.
A lot of people think because they smell fuel mixed with the oil that the fuel pump diaphragm went bad. 90% of the time that is not the case. Mercury even states and so does a lot of marine techs that the fuel vapors will pass through the diaphragm membrane. I have a brand new raw water pump and new fuel pump and I have verified that this is true. Replacing the oil in the fuel pump eccentric cavity is a must every season.
 

HitIt

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A lot of people think because they smell fuel mixed with the oil that the fuel pump diaphragm went bad. 90% of the time that is not the case. Mercury even states and so does a lot of marine techs that the fuel vapors will pass through the diaphragm membrane.
Well, I agree that the diaphragm is not bad most of the time but there is certainly not just fuel vapor getting by. I swapped the oil out after 10 hours of runtime on a new pump and it was definitely not the consistency of the drive oil I put in. It was waaaaay thinner and smelled like raw fuel. I know it wasn't water since oil and water don't mix.
 

HitIt

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If you search the interwebs, there are tons posts about fuel mixing with the oil even with a good pump. For example, see this OSO thread:

 

H8Plow

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If you search the interwebs, there are tons posts about fuel mixing with the oil even with a good pump. For example, see this OSO thread:

Yep, exactly why after every season the raw water pump oil gets changed.
 
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