Re: 1985 Johnson overtemp. sensor
RBC.... I suggest that you obtain a proper service manual before you attempt to do any work on the engine to avoid any expensive mistakes, However.......<br /><br />The "L" shaped bracket that is attached to the cylinder head and has a long brass heat sensor screwed into it is an accessory item. It is not a item that is equiped with the engine.<br /><br />As such, any wiring that would be connected to it would be seperate from the engine harness wiring.<br /><br />That item is a sensor that operates a water temperature gauge. If you have such a gauge, there should be a tan wire attached to the gauge at a terminal marked "S" (usually "S"). Someone may have changed the wire to another color but at any rate, trace that wire back to the engine area. That is the wire that should be connected to that long brass heat sensor.<br /><br />There are other tan wires on your engine that are part of the instrument/engine harness assembly which are necessary to operate the "VRO" and "Overheat" horn warning alarm.<br /><br />You are mistakenly connecting the engine harness tan wire to the wrong sensor, grounding the warning horn circuit which results in having the horn sound.<br /><br />Look at the cylinder head, near the upper portion of the head. You will see a "tan" wire protruding from the head there. That wire is connected to the overheat sensor that is inserted into and as such is part of the cylinder head. This item is what you want to conect that engine harness "tan" wire to, which if connected properly will cause the warning horn to sound off should the engine overheat.<br /><br />At the back of the VRO pump, there should be either 3 or 4 wires leading to a rubber plug type connector. One of those wires should be "tan" also which would be the circuit for the VRO pump warning system.<br /><br />Now, if the VRO pump exists, should it fail, the warning horn would sound every other second. If the engine overheats, the horn would sound steady and constantly.