Home › Forum › Ask A Member › 1985 johnson 9.9 running temp › Re: 1985 johnson 9.9 running temp
9.9/15s, especially salt water ones, have a chronic problem of a water tube restriction at the base of the power head. The design of the tube’s rubber grommet allows it to be able to close in as corrosion builds, cutting off water flow. The tell tale doesn’t really tell this tale, if you will. You have to pull the power head, remove the exhaust tuner that holds the water tube and clean out the corrosion. It is such a wide spread problem that I would not trust a single one of them to cool properly, unless I knew that service was recently done. Usually, the thermostat will be stuck OPEN, from having run hot so long. Not to be argumentative but I would like to say that I personally have never seen significant corrosion build up in the water jackets; although there is always a first time.
Long live American manufacturing!