Mercury 525 Service

[FROGMAN524]

Are you doing the install yourself? If so it’d be awesome to see the whole job, and if you decide to do the drain job the part number for the drain plugs is (10-79953Q), and you’ll just need the drill bit (5/16”) and then a tap (3/8-16)

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I’m going to try and get it done between this weekend and next by myself. Thanks for the part numbers I’ll get the drains ordered as well.


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[FROGMAN524]

So the 12th photo in my pump oilbath drain how to, has a slight view of a little vent port, is that where the kit you got attaches? Also what exactly is it supposed to do?

Ok here are the install instructions.

 

[Lavey 29]

when we use to see alot of the mechanical fuel pumps / impeller housing set ups after merc got rid of the lower drain plug below the fill plug. We use to do the same drill at the bottom - tap for threads and install a bolt & gasket that can be taken out with a box end wrench or a small socket for easy access without removing the unit.

 

[02HoWaRd26]

Ok here are the install instructions.

View attachment 976517

So you have the Hardin housing or the factory Mercury one? The link only brought up their pumps not the Merc one.
Seems like a pretty simple solution, as long as you never over fill it, as the 90° fitting looks to be above the fill hole.

 

[FROGMAN524]

I’ve got stock housings but they said I can just drill and tap with 1/8” NPT.


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[02HoWaRd26]

Thanks to Frogman524 for digging up some old gold!

Go to www.speedwake.com

if you are not a member, you have to register.

Then go to this thread, it's a sticky under the "Technical Forum"

http://www.speedwake.com/upload/showthread.php?s=&threadid=18967

Pictures and all, step by step. The best instructions I've found on the net. This is for the HP 500's but I think the 525's are the same.

 

[02HoWaRd26]

Any opinions on replacing the thermostat? Mine runs awesome, he’ll it’s running way better than last year honestly. But my VesselView gave me a notification that the thermostat is 5 hours from inspection, my opinion is typically if needed an inspection and removal i may as well just replace it.

 

[Springfield]

Any opinions on replacing the thermostat? Mine runs awesome, he’ll it’s running way better than last year honestly. But my VesselView gave me a notification that the thermostat is 5 hours from inspection, my opinion is typically if needed an inspection and removal i may as well just replace it.

I don’t think your penalized for early maintenance. Go for it, it’ll give you something to do for the next 5 minutes.

 

[02HoWaRd26]

The idler/tensioner pulley adjuster bolt on my engine was a little stripped so decided to order a new one as well a new nut while at it.

Start by loosening the pulley to drop the belt, than remove the three bolts that hold the bracket on. (Top two are 5/8” and the bottom is 9/16”)

Now you see how the adjuster bolt works on the plate.

Simply remove and replace the bolt. Than reverse the steps. Super easy and cheap vs fighting a stripped bolt head.

Will update next week when i clean the heat exchanger replace the gaskets and thermostat, than swap to the ss Hardin impeller housing.

 

[02HoWaRd26]

Got an email from Rick at FST Performance, they now have a direct fit fuel water separating filter to fit the Mercury 525.

It is the FST RF51

 

[Runs2rch]

Got an email from Rick at FST Performance, they now have a direct fit fuel water separating filter to fit the Mercury 525.

It is the FST RF51

That should be a replacement for all Mercury engines that use a spin on water separating fuel filter.

 

[02HoWaRd26]

I gotta look this up every time i do it, so great place to save a screenshot right here!

Belt diagram

 

[02HoWaRd26]

Ok here are the install instructions.

View attachment 976517

So i had mine out to do a seasonal refresh on impeller, wear plates, oil change on pump etc and decided to get the vent kit while at it. Wasn’t a complicated task but id call it a skill level 2 as there’s drilling and tapping.

 

[Shlbyntro]

just curious, what gave you the impression that part needs to be vented?

 

[02HoWaRd26]

just curious, what gave you the impression that part needs to be vented?

Well had fuel leaking into the pump portion and this is said to be a fix.
I as well threw on a new Merc fuel pump as well just as it’s easier to be safe and have a possible spare than continue to have fuel in the pump.

 

[Shlbyntro]

I've never heard of that before. all that means is you needed a new fuel pump

 

[02HoWaRd26]

I've never heard of that before. all that means is you needed a new fuel pump

It’s a kit that’s pretty common, so i did it. Was a point of discussion prior in this thread so i chose to document it for anyone looking to do itself. I enjoy your posts most the time but seems if you wouldn’t do something or it’s not part of a book guideline you like to crap on people doing things.

Again as this is a thread on service items on the 525 and was a point of discussion in this thread seemed pretty simple for me to take a few photos as i did the work so that others could see the how to.

 

[Shlbyntro]

It’s a kit that’s pretty common, so i did it. Was a point of discussion prior in this thread so i chose to document it for anyone looking to do itself. I enjoy your posts most the time but seems if you wouldn’t do something or it’s not part of a book guideline you like to crap on people doing things.

Again as this is a thread on service items on the 525 and was a point of discussion in this thread seemed pretty simple for me to take a few photos as i did the work so that others could see the how to.

not crapping on anyone. just offering my perspective from a professional stand point and trying to save the inmates (including you) extra work and dollars. but if that's how you read it, I'll quit offering advice

 

[Nanu/Nanu]

Just out if curiosity are all of these 525 motors equipped with mechanical fuel pumps or was there an electric pump option?

 

[02HoWaRd26]

Just out if curiosity are all of these 525 motors equipped with mechanical fuel pumps or was there an electric pump option?

It’s both, a low pressure pump that then feed the electric pump. Means the electric pump isn’t sucking from the tank it’s being fed via the manual low pressure pump, which it’s doing the suction from the tank.

 

[Nanu/Nanu]

It’s both, a low pressure pump that then feed the electric pump. Means the electric pump isn’t sucking from the tank it’s being fed via the manual low pressure pump, which it’s doing the suction from the tank.

Ok that makes sense. I was thinking man thats pretty wild if these engines are still relying on a mechanical fuel pump. Well nice job on the project.