Re: Adding a temp gauge to Evinrude 70hp
Let's get the facts straight here folks. Just because the water pump is providing a good stream of water from the telltale (its not a pisser) does not mean the engine is not overheating. Water temp and water pressure are two separate functions. A temperature gauge tells you the engine is or is not operating at the proper temperature. The water pressure gauge tells you the pump is working. The key is to install a new impeller when you install a water pressure gauge. You then note idle and wide open throttle water pressure. Later, any deviation from these numbers indates a water system problem. Temperature gauges come in two varieties -- 1) water temperature and 2) cylinder head temperature. A sender that screws into the block and is in contact with the water is a water temp gauge. A sender that mounts on the cylinder head with a "Z" (or other style) bracket is a cylinder head temp gauge. Cylinder head temps will rise much faster than water temp. The ideal setup is to have both gauges. But again, just because you have water pressure does not mean your engine is not overheating. A stuck thermostat is just one example. Removing a headbolt on a highly corroded engine can be an issue. Retorque is required after installation.
Deadending the telltale at the pressure gauge is also not a good idea. If the pressure gauge suddenly shows Zero, how do you know whether the gauge is bad, the pump is bad, or the intake is plugged. If you "T" the gauge into the telltale, it's a simple matter to turn around the view the telltale. If it shows a stream, the gauge went bad. If not, you have a pump or clog issue. Keep existing functions functioning -- they are there for a reason.
