99 Johnson 200 Blow Off Valve Cover Leak

[thllc]

For the past two seasons the blow off valve cover has leaked (noticeable drips at idle) in a couple of locations around the cover where the plastic meets metal. This cover does not call for a gasket of any type. How do I solve my leak? I am worried about tightening the bolts too tight. After 6 years, could the plastic cover be warped, and just need replacing?

 

[OBJ]

Re: 99 Johnson 200 Blow Off Valve Cover Leak

Hi Tom...welcome to iboats.<br /><br />Could you describe the "blow off valve". Not sure what you are referring to.<br /><br />Thanks.

 

[seahorse5]

Re: 99 Johnson 200 Blow Off Valve Cover Leak

Your blow off valve, sometimes called a pressure relief valve or poppet valve, has a rubber seal lightly pressed inside the cap that keeps the water from leaking out. Remove the hoses and the cap, but be aware of spring pressure if the seal is loose. Make sure the engine block cavity is cleaned of any salt, corrosion, or debris before installing a new seal.

 

[OBJ]

Re: 99 Johnson 200 Blow Off Valve Cover Leak

Looked at the engine parts manual Seahorse and can't find the relief valve. Where's it located at? Don't get to many 200's in this neck of the woods....

 

[seahorse5]

Re: 99 Johnson 200 Blow Off Valve Cover Leak

OBJ,<br /><br />The blow off valve is on the back of the crankcase toward the upper port side. It is a plastic cap with two 5/16" ID hoses that go to each thermostat cover. This is only on 1993 thru 2001 3.0L engine blocks. <br /><br />For a J200PLEEN model in PartSmart, the cover is item #88,part number 337249 and the seal is #335981. The valve tip itself is item 18, part #344202.

 

[OBJ]

Re: 99 Johnson 200 Blow Off Valve Cover Leak

OK! Found it. Thanks Seahorse!

 

[thllc]

Re: 99 Johnson 200 Blow Off Valve Cover Leak

I took it apart and cleaned it all up. Still leaks. I did read manual and it calls for 60-80 lb torque on the bolts. Is this for real? I'm afraid of tightening the bolts too much for fear of stripping the threads in the engine/block. My local marina/parts guy suggested using the blue silicon/gasket material to help seal it, so I tried this yesterday. Have not had a chance to get back to the boat and check for leaks now that it has dried.

 

[FAV453]

Re: 99 Johnson 200 Blow Off Valve Cover Leak

I made the mistake of loosening that valve and can't get it tight enough so it is leaking. Hard to get the bolts off thus I belive the torque spec is that high. Problem is that the heads are now stripped so I need new bolts before I try. Did you get it to stop leaking Tom?

 

[thllc]

Re: 99 Johnson 200 Blow Off Valve Cover Leak

Yes, leak stopped after applying gasket material. Although it did still have a small drip, even that stopped after the engine warmed up. Possible heat expansion solved it ultimately. Thanks eeveryone!

 

[rodbolt]

Re: 99 Johnson 200 Blow Off Valve Cover Leak

Tom<br /> check your reading, that should have been inch pounds not foot pounds . that 1/4 20 screw wont take much more than 80 inch pounds.<br /> glad it slowed, I use perfect seal or gasket maker on the surface flange.<br />yes they do tend to warp with age.

 

[thllc]

Re: 99 Johnson 200 Blow Off Valve Cover Leak

ah, well that explains that. That's what I get for trying to use a torque wrench I got a few years back for a Porsche, on an outboard