2001 Merc XR6 - Poppet valve rebuild

[DeudeMann]

Per the title I have a 2001 Merc XR6 and just finished rebuilding the poppet valve assembly. I removed it from the motor, disassembled it, and replaced all the soft parts including the diaphragm with new Merc parts ordered per the Merc parts diagrams for my serial number. New gaskets as well.

During a test this morning I noticed there was some water leakage from the weep hole on the poppet valve case which is not normal of course; AFAIK the weep hole is there to show if the diaphragm is leaking. I checked the service manual and there do not seem to be any special procedures (or any procedures at all really) for reassembling the poppet.

Is there any special voodoo required for reassembly? Does the edge of the diaphragm require sealant?

The old one appeared to be OK during disassembly though there was a lot of gunk buildup between the large washer and the diaphragm.

Thanks

[tlwjkw]

sometimes tha large plastic washer will get slightly warped and ya won't notice it unless ya really lookin' for it.. we replaced it with one cut from aluminum stock.. ended our problems with "unknown" drips......

[DeudeMann]

sometimes tha large plastic washer will get slightly warped and ya won't notice it unless ya really lookin' for it.. we replaced it with one cut from aluminum stock.. ended our problems with "unknown" drips......

Thanks. I'll be removing it again and will check that. I replaced that as well with a new one but it could have been warped in storage.

[DeudeMann]

Update FWIW: I removed it from the engine and everything looked OK so I think I just pinched a gasket or something during installation. So I reinstalled it but this time I used a very light coat of marine sealant to hold the gaskets in place. Installation was much easier.

[pcrussell50]

Update FWIW: I removed it from the engine and everything looked OK so I think I just pinched a gasket or something during installation. So I reinstalled it but this time I used a very light coat of marine sealant to hold the gaskets in place. Installation was much easier.

Does that mean it’s not leaking?

-Peter

[DeudeMann]

Does that mean it’s not leaking?

-Peter

TBD - I have not tested it yet.

[pcrussell50]

TBD - I have not tested it yet.

Got it. Thanks. Please report back when you do. I'm in the middle of a poppet rebuild too. I'm holding off on it and doing other things first until I hear back from you.

-Peter

[DeudeMann]

It may be a few days... The boat is not in a place where I can run it and I won't be able to move it right away.

[DeudeMann]

FWIW if you are in a hurry to finish... I am 95% sure it was a gasket out of place because everything else looked OK. What I did was:
- I first used 3M 5200 to adhere the two removable plates together with one of the two gaskets and the poppet valve assembly in place; I used a very light coat and then clamps to hold them together and in alignment while the adhesive set; I gave it an hour.
- In parallel I used the same 3M 5200 to attach the second gasket to the block.
- Once everything was set it was very easy to reattach the poppet/plate assembly to the block since everything was held in place.

It will be harder to disassemble next time (if ever) because of the sealant but I will deal with that for the assurance it is assembled correctly.

Hope this helps

[DeudeMann]

For more clarification here is the parts diagram. Green shows the plates/poppet assembly. Yellow shows attachment of the second gasket to the block.

[pcrussell50]

Right now the powerhead is on a workbench. Which means I can lie it on it’s side for poppet assembly and install. Do you think that will help and maybe I won’t need adhesive because of it?

-Peter

[DeudeMann]

Right now the powerhead is on a workbench. Which means I can lie it on it’s side for poppet assembly and install. Do you think that will help and maybe I won’t need adhesive because of it?

-Peter

Yes that makes a huge difference IMO. The bolts are a tight fit with the gaskets so that helps with alignment. You could lay it on its side like you said, and watch everything carefully as you assemble it. Get it in place, then use a weight to hold the assembly down while you tighten the bolts.

The spring load on the poppet is the only thing that makes it tricky since the spring load wants to push the assembly away from the block. It's essential though to how it operates. Also note there is a rubber seal in the block for the poppet.

[DeudeMann]

Got it. Thanks. Please report back when you do. I'm in the middle of a poppet rebuild too. I'm holding off on it and doing other things first until I hear back from you.

-Peter

Reporting back. I ran it on the muffs and it is not leaking.