Re: water flow question 76' johnson 135 v4
The temp switch is at the end of the brown wire, nested in the head. When that switch senses 212 degrees, it will short to ground, sounding the warning horn in the control box. When the powerhead temp goes back down to 175 degrees, the switch will open and the horn will quit sounding. On that 76 engine, you should have only one switch, (it is possible that a late 76 might have two switches-one in each head.) A brown lead with a knife end on it. It will connect to another brown lead with the same knife connection in the powerhead main engine harness. Usually the wire end has a round black rubber boot which surrounds and protects the connection. There should be a mist which comes out of the two exhaust relief ports at the top of the midsection. When starting cold, the thermostat will open after a minute or so, and immediately a watery mist will start to come out of those ports. When that happens, you know the vernatherm (thermostat) has opened. Usually the misting is similar out of both ports. If the engine is new to you or you have never serviced the vernatherm, you might want to change it and check the pressure relief valve at the same time. This is not always an easy job on a bubble back engine.
