Re: Merc water pressure relief valve
 

Klaw-Performance marine use to make their own popet valve system. It was somewhat simular to Merc's design, but not as evolved. It also costed about the same....

I'd first get on the water, and then address the problem. You may just get lucky and not need them.

Re: Merc water pressure relief valve
 

Looks simple enough to make and simple in design (Thinking here) ....
any patents? $100 is kind of high in my opinion.

Re: Merc water pressure relief valve
 

The question remains, what are the connection sizes for Part # 863208A3?

Re: Merc water pressure relief valve
 

1 1/4" on the input and output and 1" on the relief. Hope to hook mine up this week. Will let everyone know the results after next weekend.

Re: Merc water pressure relief valve
 

Faster,
You are the man! That is exactly what I wanted to hear.
Placing my order today.
Thanks!
Russ

Re: Merc water pressure relief valve
 

I got my relief valve plumbed in Friday night and ran all weekend. Before I was pegging the gauge past 35 psi at anything above 55 mph. With the valve I am running between 20 and 25 psi regardless of speed. :)

Re: Merc water pressure relief valve
 

Where are they installed on a system? After the sea water pump?

Re: Merc water pressure relief valve
 

I put mine between the sea water pump and crossover.

Re: Merc water pressure relief valve
 

Do you think that the direction of water flow, as stated in the instructions, has a bearing on it's performance? I have seen pics on this site where the over pressure discharge is opposite of what's stated in the Mercury instructions.

Re: Merc water pressure relief valve
 

Here is a picture of the over pressure discharge opposite of the supply flow.
Personally, I don't think it matters due to the fact that when it opens the water will take the path of least resistance, regardless of direction.