Mercury 525 Question

[Mikes56]

Long time lurker, new member and I have a question about my boat. Hope someone can help me.

I've got a Mercury 525 in my 2008 Topcat I, and a very reputable shop told me that as part of the maintenance I need to change the gear oil in the fuel pump or some kind of pump. Apparently there is a small housing that has two meshing gears that has gear oil in the reservoir.

Anyone know what I'm talking about? I can't find it. It's supposed to be on top of the engine somewhere.

 

[Duck'ed_Up]

Long time lurker, new member and I have a question about my boat. Hope someone can help me.

I've got a Mercury 525 in my 2008 Topcat I, and a very reputable shop told me that as part of the maintenance I need to change the gear oil in the fuel pump or some kind of pump. Apparently there is a small housing that has two meshing gears that has gear oil in the reservoir.

Anyone know what I'm talking about? I can't find it. It's supposed to be on top of the engine somewhere.

Yup 100% true. It’s on the sea water pump.



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[Runs2rch]

Sea pump. Impeller and change gear oil in it. Bottom left of motor. Hard to drain and fill while installed.

 

[4Waters]

Welcome to the asylum, we will need pics of the boat and wife/GF, you will win a prize if you get a pic of all 3 together.

 

[Mikes56]

Thanks for the quick replys. I recently changed the rubber impeller because I sucked up some sand. When I was changing that, I didn't see anything that looked like a reservoir that would hold oil. Did I just miss it?

 

[Mikes56]

As far as the photos, I'll try. My wife is a good sport. We get to Havasu 3-4 times a year, and have a Timeshare at The Nautical.
We're actually thinking about moving there in a few years when my wife retires. Each time we go, we get a little closer to moving there.
Spent New Years there at a buddy's house and drove the CanAm all over town for the 3 days. I think we had more fun on the CanAm than we've had on the boat

 

[Runs2rch]

Thanks for the quick replys. I recently changed the rubber impeller because I sucked up some sand. When I was changing that, I didn't see anything that looked like a reservoir that would hold oil. Did I just miss it?

You probably just pulled the impeller housing off. It is attached to the actual sea pump. You will see mechanical fuel attached to it. Has a fill plug on the side, but no drain plug.
Easy way is to remove the complete assembly and take it to your bench.

 

[Riverbottom]

I have removed the fuel pump, and sucked the gear oil ( contaminated with fuel ) out with a turkey baster and replaced mid season, rather than remove the whole assembly.

 

[Mikes56]

I have removed the fuel pump, and sucked the gear oil ( contaminated with fuel ) out with a turkey baster and replaced mid season, rather than remove the whole assembly.

Fuel pump? I thought it was the sea pump?

 

[02HoWaRd26]

Those 525’s are stupid you should take it out and give it away! Let me know I’ll help cause I’m a sport

 

[Racey]

There is no reservoir, look at the front housing of the waterpump where the fuel pump is attached, you will see 1 or 2 straight blade screwdriver plugs, the one oriented at the top is the fill level, take it out with a screw driver and use a squirt bottle to fill to that level

 

[wsuwrhr]

Leave it to Racey mcracerson to make it plain as day. Good man.

There is no reservoir, look at the front housing of the waterpump where the fuel pump is attached, you will see 1 or 2 straight blade screwdriver plugs, the one oriented at the top is the fill level, take it out with a screw driver and use a squirt bottle to fill to that level

 

[wa4stroker]

Fuel pump? I thought it was the sea pump?

Both have oil and need periodic service


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[Racey]

Fuel pump? I thought it was the sea pump?

So the deal is when GM migrated from the Mark IV to the Gen V big block they eliminated the mechanical fuel pump boss from the block casting, so no more camshaft driven fuel pumps, Mercury put a cam inside the waterpump body to drive a standard style cam diaphragm fuel pump to solve this. It also has the added benefit (though rare) that if you throw the waterpump belt, you kill the fuel supply and the motor shuts down)

 

[robby dmax]

Welcome to the asylum, we will need pics of the boat and wife/GF, you will win a prize if you get a pic of all 3 together.

You forgot to mention he needs to PM 460 for his RDP swag package

 

[28Eliminator]

For what it’s worth, the housings corrode badly and leak, mixing the water with oil (as well as the fuel from the FP). There’s a guy on eBay selling new housings for less than 1/2 what merc gets for it.

 

[Mikes56]

Thanks for all your help guys. I'll get into the engine compartment and take a look.

 

[Runs2rch]

View attachment 752855 View attachment 752856 View attachment 752857 For what it’s worth, the housings corrode badly and leak, mixing the water with oil (as well as the fuel from the FP). There’s a guy on eBay selling new housings for less than 1/2 what merc gets for it.

That is a Dennis Moore pump right?

 

[28Eliminator]

That is a Dennis Moore pump right?

No idea... could be, I know he makes a bunch of stuff.


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