Re: Installing waterpump function indicator
My '77 Evinrude 85 HP, model 875799S, only has heat-sensor horn to warn
of overheating. I've heard that a small tube from water jacket can be installed to serve as backup to horn. Can someone tell me best place where the hole should be drilled and threaded to install this feature?
It's called a water pressure gauge. It tells you the pressure that the pump is putting out. Teleflex, and I believe Faria and other aftermarket gauge companies sell them, so you shold be able to get a decnt match for your current gauges if that's important.
I don't believe it's the most precise gauge in the world, but it definitely tells you if you have strong pressure or if it disappears or starts getting weaker. I couldn't tell you exactly what my current engine puts out, I just look at it to see that it has some pressure at idle, goes up higher when I give it some rev's and that it stays there when I look at it from time to time. Saves me from looking over my shoulder at the telltale.
As for installation, either the installation will be clear on the gauge instructions, or someone here can tell you exactly where to install. It's going to be easy none the less.
The gauge has a hollow tube runnign from it to the engine (tube comes with gauge kit, or you can buy similar tubing at any place that specializes in tube and hose sales for commercial companies). Kind of like a semi-rigid pitot tube type speedometer. Then, the electrical hookups to the gauge are like most others: a purple wire to the ignition (which I just piggybacked to the tach), a ground wire and if you want it to be lit, a wire to the light switch. There's no "sender" electrical connection, the sender is the hollow tube which converts water pressure to air pressure which the gauge reads.
I've installed two, but both are on somewhat mroe recent V6's - one and ~82 or 83 and the other a '90. The older engine was dead easy - the water pressure tube was just "T'd" into the tell tale. The other was a little more complicated, but the gauge instructions showed me where, once I figured out how to read their schematic type drawings.
