1999 Johnson 40hp Water Temp Light

[jeff_32]

My 40hp runs great and then the system check water/temp light comes on and bogs down. The impeller and thermostat are both new and looks like great water circulation. I unplugged the temp sensor and the problem remains. What should the temp be on the block/thermostat housing be? The water coming out of the tell tale is not hot.

 

[Crosbyman]

tell tale tells you the water pump is working

getting hot above 140-150 means circulation around cyl water jackets is poor.

if thermostat is ok then water flow is impeded somewhere by crud, old impeller fins stuck in the ph, salt ? etc....

you can always pull the cyl head and check water jackets and water orifices

if not try RID LYME or similar products to flush the PH

 

[jeff_32]

I dropped my infrared thermometer, need to get another. But I can put my hand on the block and it isn't hot.

Yesterday I took it out on the water and ran great for a a few minutes, then the water/temp light and buzzer start along with the surging, S.L.O.W. mode. I removed all sensors and disconnected the wire harness and key switch and installed a key switch directly to the engines wire harness. I still have the same problem. Could this be a bad engine harness and or bad stator?

 

[Crosbyman]

I'll let the expert chime in... SLOW or SAFE mode is the result of a CPU controlled engine decision ... you may have blink codes flashing ?

do u have manual ???

 

[jeff_32]

I'll let the expert chime in... SLOW or SAFE mode is the result of a CPU controlled engine decision ... you may have blink codes flashing ?

do u have manual ???

Yes I have an OMC service manual. I'm not getting any bad tests with the stator or the new power pack. I pulled the stator today and don't see any melting from it as I was told to look for.

Could the stator be the problem once it gets hot? I don't want to be a parts changer, but so far my tests I've done according to the service manual aren't giving me any direction.

 

[ct1762@gmail.com]

Yes I have an OMC service manual. I'm not getting any bad tests with the stator or the new power pack. I pulled the stator today and don't see any melting from it as I was told to look for.

Could the stator be the problem once it gets hot? I don't want to be a parts changer, but so far my tests I've done according to the service manual aren't giving me any direction.

if its going into SLOW mode, only 3 things it could be. all done by process of elimination. #1 make sure tan temp wire isnt near a plug wire. #2 disconnect tan wire and retry. if it still goes into limp, test diode in harness . your newer harness makes this really simple. if its fine, its the pack. i deliberately left out checking head temp at speed. very possible you are ok at idle, but the t stat grommet is stuck to the housing and not able to lift off its seat. another issue i see with these 2 cyl loopers is the water pump housing grommet is pinched/torn, which restricts water flow. if it is overheating when on plane, drop gearcase and do the pump.