Yes, That's a perfect example for when to use it. Tap it into the hose anywhere before it goes into your cross over.:p

I just order a pair of these. Does anyone know what size hose it takes so I can get some today? It looks like maybe 1" from the picture?

1" hose Inside Diameter (ID)

ttt

I am switching over to crossovers. Can I dump into the fitting on the Gil exhaust? If I can, I only need to change two of them to the straight pipe piece from the tee type.

I don't think the fitting in the exhaust will flow enough, and if it did, I don't think it would be fast enough for pressure spikes. A threw transom fitting gets you the best results.

Re: Merc Water pressure relief valve #
 

Could someone please send me the pictures on this thread via email? My membership ran out and I need to fix this asap. Will be renewing membership shortly but in the meantime I need to figure out the best way to plumb the relief valve. My email is: [email protected].

Thanks,
Dave

Re: Merc Water pressure relief valve #
 

Done :)

Re: Merc Water pressure relief valve #
 

Why is your water pressure so high in the first place? I assume this is while running on plane. We use pop off valves but for pressure spikes, not to counteract high pressure. Are you water pick ups on the bottom of the boat? I just read this and have no idea what boat or drive combination you have but if your problem is too much water pick up you're leaving some speed on the table. If your outlet is restricted and your dumping the water off that could cause other problems

Re: Merc Water pressure relief valve #
 

I'm not exactly sure why the water pressure is so high. I don't have a pressure gauge which is one of my priorities this week. Just went through an engine rebuild and have been finding a few gremlins. One of them is some moisture in the combustion chamber. I changed plugs this weekend and had water droplets on each of them on one bank of cylinders. I was told that the water pressure pegged out a 35psi gauge and when using an oil pressure gauge the water pressure was 45psi. I have checked and double checked risers and gaskets with no obstructions. I have checked the oil cooler for leaks and all is good. I'm not sure why the high pressure but the engine builders "fix" was to reduce the flow to the raw water pump by blocking off one of the pickup holes in the lower unit. I wouldn't think this is the answer as this is starving the pump more than it is anything isn't it? My guess is that water might be getting past the head gasket or intake manifold gasket with pressure that high. That is why I am going to install the relief valve.