[fisherman_freddy]

HiI have a 1987 3 cylinder Merury Mariner which looses power after 3 miles at 4k revs. If I let her cool down she runs again at power but then drops again. Other symptoms are blipping at speed having lost power. Have check compression, plugs, water comes out of tell tale pipe, timing ok, renewed carb float valves but no improvement.I suspect overheating but engine feels ok - hot to touch but not too hot. I have also checked the warning horm - ok. Does anyone know how to check the temp sensor just to double check ?.Any clues to what the problem is would be gratefully received.

[Moody Blue]

Is this a new problem ? Are you using the oil injection system or pre-mixing ? When was the last time the water pump impeller was changed ? Is the vent on the gas tank open ?To check the horn operation, turn the key to RUN and remove the sending wire from the sensor and touch it to ground. The horn should sound.To check the sensor remove it from the engine. Using an OHMMETER check for continuity between the wire terminal and the body of the sensor. It should be open circuit or no connection. Drop the sensor into boiling water for a minute then remove it and quickly do the same test. It should now be a closed circuit or a short.

[Laddies]

Test the sensor with a ohm meter in hot water on a stove, the popit valve could be stuck not letting the motor to dump water at high speed