Heat alarm on Johnson 115 OceanPro

Hello over there,<br />Got a Johnson 115,HJ115SLEUA, -97 OceanPro. Got out for the second time this summer.Last time no problem. Engine would´nt go more than 3000 rpm for a start. With a bit tilt and trim it came up to 4500 rpm.(Should bee 5500 rpm) After 5-10 min. the heat alarm sounded and it lost power. I checked the cooling waterjet and it was ok. I could run the engine at not more than 3000 rpm. Than it starts vibrating. The bulb was not hard, but it didn´t help pumping it hard. I´ve got fresh gas and new fuelfilter and right plugs. Why the heat alarm when the colling seems to be ok?

Re: Heat alarm on Johnson 115 OceanPro

Welcome to the forum!<br /><br />The telltale/ water jet only tells you that the water pump is indeed pumping water. The telltale is only a visual check to see if water intake is not pluged and that water is avalable to circulate through engine.<br /><br />It does not mean water is circulateing as it should through engine block.<br /><br />You could have a blocked water passage. Or perhaps you have thermostat stuck closed or at least partialy closed.<br /><br />Any time your over heat horn sounds off...STOP.<br />And find out why.<br /><br />You can check for over heat while running on muffs at home with garden hose. let engine for 30 minutes or so or until horn sounds off. STOP and put your fingers on engine heads. If you cant hold it for a couple seconds at least. then its to hot.<br /><br />You can check with thremo melt sticks. they are avaliable from auto supply stores.<br /><br />motor should not run above 175 degrees FH. nor below 125 FH.<br /><br />Good Luck!

Re: Heat alarm on Johnson 115 OceanPro

Sounds like its time for a new waterpump.