'75 850.. temp gauge?

[centerline]

the previous installation of the motor had a temp gauge at the helm and was wired in to the harness.. it was all cut away when it was removed from the donor boat.... the question is, did the merc 850 have an optional engine temp sender?... I have never seen one before on an older outboard, but there are other options that I have never seen before also, such as the merc water pressure gauge mounted in the dash....

is there a list somewhere of all the options that were available for these engines, AND how they connect into the system?... I have the Seloc manual, and it shows the basic system wiring, but it does NOT show how the gauges and peripherals wire in to it...

 

[Chris1956]

A water temp gauge is useless on that motor, as it does not have a thermostat. You will see zero water temp most of the time, and if it overheats, it will do so very quickly.

A water pressure gauge is a good one to have. You can monitor the water pressure, especially if you hit some sand or mud. Water pressure gauges are mechanical. You will run a tube from the motor to the dashboard. Power for gauge lights can come from tach or MerControl plug.

 

[centerline]

A water temp gauge is useless on that motor, as it does not have a thermostat. You will see zero water temp most of the time, and if it overheats, it will do so very quickly.

A water pressure gauge is a good one to have. You can monitor the water pressure, especially if you hit some sand or mud. Water pressure gauges are mechanical. You will run a tube from the motor to the dashboard. Power for gauge lights can come from tach or MerControl plug.

Chris, thank you.... what you describe has been my experience in the past with overheating on outboards, but I dont know it all and was wondering if maybe the temp gauge was a mod that worked..... so now I wont bother with it.
the water gauge has been installed in the dash, and I found the tube to be plugged solid so it couldnt possibly have been working on the donor boat.... but when im ready to connect it to the motor, does it connect direct to the pisser outlet, or is there somewhere else that it should properly connect?

AND, do you know the 2 different part numbers for the hyd tilt/trim hoses for these older motors? thanks again for the help...

 

[Chris1956]

The crowleymarine web site should help with the hydraulic hose part numbers.

As for the pressure gauge. Some inline motors have a plug on the cylinder head water jacket (between the spark plugs). If you have one, use it for the pressure gauge. If not screw a brass tee into the telltale and run one side to the telltale and the other to the gauge. Water pressure is not much, so hopefully your gauge reads 0-15 PSI.