Installing Water Pressure/Temp Gauges - Need Some Help!!!

[Mercury60]

Hello all, I've been lurking on this site for quite a while and have learned a great deal from you guys. I guess its finally time for me to start participating! I could use some help on installing some water pressure and temp gauges on my 3cyl, 60hp Mercury outboard. It is a 1986(ish) vintage with serial number OB126644.

I've been suffering from a very weak telltale at idle (which I am going to start another thread on). The impeller and gaskets are new so I want to install some gauges to know exactly what is going on.

Where is a good place to install a pressure gauge? There is a hose that goes from the top of the head to the bottom and connects to the telltale...is this a good place? Is it before or after the thermostat? I would prefer to be before the t-stat to know what the pressure is at all times, not just when the t-stat is open. Are there any bosses in the head or block to unscrew? If so, where are they? I really don't want to drill.

How about a temp gauge? In addition to a pressure gauge I would prefer a water temperature gauge over a cylinder head temp gauge. If I am able to screw into the head/block with the pressure gauge....can I use this port for the temp gauge as well? It would be nice to kill two birds with one stone.

Thanks in advance!

 

[Mercury60]

Re: Installing Water Pressure/Temp Gauges - Need Some Help!!!

Holy smokes, I made it to the 3rd page in 12 hours! Anyone?

 

[Moody Blue]

Re: Installing Water Pressure/Temp Gauges - Need Some Help!!!

Not familiar with your specific motor but there is usually a threaded port (1/8" npt) either on the head or top of the block. The port will be plugged with a hex headed (brass?) plug about 7/16" in size. You will need to experiment with the best place to install the take-off for the pressure gauge.

Some say in the telltale line, others direct to the block (head or top of block). I tried the telltale with very poor results. I then installed a brass "T" into the port on the head and connected both the pressure gauge line and a temperature sender. Worked great. My idle pressure is about 2-3 PSI and WOT about 12PSI. I used a 0-15PSI gauge and get almost full scale reading at WOT.