Depends. If you are measuring on the outlet side if the stat you will not be getting a true reading. Try to use a port on the intake or or block for your gauge. Put the valve right before your cir pump.

Alright, i'll change the water pick off.

The valve on the other hand, i'm curious the theory on placement on that. If it's before the circulation pump, the higher water pressure would be going through the sea pump, and oil cooler, then brought down to 25lbs potentially for the engine/exhaust; correct? Maybe the higher water pressure would help keep the oil cooler more efficient?

I'd like to get my oil temps lowwer, however i was told I have the sender in the wrong spot for that as well (currently in my remote oil filter housing). I was told to move that in a block port above the block filter pad. I havn't looked at that location yet, but I have a feeling one of two oil temp senders is there.

It needs to get the reading from a port on the intake or a block drain. The intake is beeter since the block drain location tends to clog the pressure line easily.

Roger that, i'll check into available spots on the intake tonight...

Alright, I'm confused now. I took a look at my set-up, and I do have the merc valve between the sea water pump and the oil cooler, however that hose is on the bottom fitting of the sea pump. The top fitting goes to the drive. I looked up the parts diagram a couple of days ago and it showed the bottom going to the drive??? So what gives? I ran it that way all last summer with no problems......... Are the hoses on the sea water pump backwards?

The water going the seapump goes in one inlet for a LH rotation engine and goes in the other inlet for a RH rotation engine. If you have good water flow then the way you have it is correct.

So where is the valve dumping the water????

The technical term for the difference between the pressure at which a relief begins to lift, and when it achieves full rated flow is called "accumulation". Your tax dollars paid for that knowledge, so I figured I should share...

This is typical of a spring-operated relief. We also use pilot-actuated relief valves which stay shut hard until a precise pressure is reached. When the valve is desisgned to stay open and not reseat until a lower pressure like on a nuclear high pressure system, that's called the "blowdown" value. Now that we're bored to tears, back to the regular program

Hey Jerry....
This guy needs your help with the spring number. Tried to PM you but it didn't work.

Terry

Easyrider1340.
I would appreciate your assistance in getting a part # from US1 Fountain. His profile would not let me Priv Message him. I just saw your name as one of his friends. If you could PM him my message since you are one of his friends I would be grateful.

He knows a part number for softer springs for the Mercury engine cooling relief valve # 863208A3. He stated on a post long ago that he had replaced the mercury standard spring, set at 25psi, with a lighter spring, to reduce his engine block water pressure. He stated McMaster Carr but i need the part number.

KLarson @ FirestoneLC.com, or if he can he could Priv message me if it will allow it.

thanks for your help.

Kurt Larson
Lake Charles, La

pt # 1986K18

Try that.

Thanks US1 FOUNTAIN and EASYRIDER1340.
I'm a little late getting this but i will look for this spring at McMaster Carr next week.