**PROBLEM SOLVED**1996 Evinrude SPL 50HP water temp light coming on/SLOW mode

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My engine water temp light and alarm keep coming on and the engine is not hot. Sometimes it will do it as soon as it cranks up. When it comes on the engine goes in slow mode. I can turn switch off and immediatly back on before the engine goes dead and all alarms quit, and it comes out of slow mode. I can then open it wide open and all is fine. Until, I slow down to an idle and it comes back on. I carried it to my mechanic and he checked the sensor, and the diodes in the wiring harness, and even replaced the temperature switch. Any ideas?

 

[ob]

Re: 1996 Evinrude SPL 50HP water temp light coming on/SLOW mode

Re: 1996 Evinrude SPL 50HP water temp light coming on/SLOW mode

First ,I'll ask how you determined that the engine wasn't getting hot when the overheat light lit and engine went into S.L.O.W. mode?Next,when you say sometimes it alarms just after startup ,do you mean immediately or after several seconds?

I'm thinking that the engine is overheating at lower rpms because of a worn waterpump or faulty t/stat yet at higher rpms it is delivering enough flow for cooling.It which case I would recommend replacing the waterpump impeller and seals as well as installing a new t/stat assy.

 

[hold em hook]

Re: 1996 Evinrude SPL 50HP water temp light coming on/SLOW mode

Re: 1996 Evinrude SPL 50HP water temp light coming on/SLOW mode

First ,I'll ask how you determined that the engine wasn't getting hot when the overheat light lit and engine went into S.L.O.W. mode?Next,when you say sometimes it alarms just after startup ,do you mean immediately or after several seconds?

I'm thinking that the engine is overheating at lower rpms because of a worn waterpump or faulty t/stat yet at higher rpms it is delivering enough flow for cooling.It which case I would recommend replacing the waterpump impeller and seals as well as installing a new t/stat assy.

I back the boat in the water, crank it up, 10-20 seconds later alarm comes on and goes into slow mode. Had a mechanic check it out, he checked t-stat, diodes in wiring harness, and even replaced the temperature switch. When he cranked it, it would imediatley set alarm off on water hose. The next day it ran for 2 hours and never set the alarm off. I am not a professional mechanic but I know there should be no way for the engine to overheat in 10-20 seconds. Replaced the water pump last year when it was doing this and it still set the alarm off. As for high speed and no alarm let me re-phrase that as to I can cut it off and before the engine dies completely turn the switch back on and speed up to quarter throttle and go w/o it coming back on.

 

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Re: 1996 Evinrude SPL 50HP water temp light coming on/SLOW mode

Re: 1996 Evinrude SPL 50HP water temp light coming on/SLOW mode

PROBLEM SOLVED
Took the bracked off (3 bolts) that holds the power pack and ignition on and the tan wire was behind the bracket and had rubbed against the engine until it had got through the wire coating and was shorting out