86 50 HP Evinrude alarm

[njbob]

Hi, I have an 86 Evinrude 50HP. Latley I have been getting an alarm, the constant on type. At first I thought it was the VRO system but after reviewing the posts here I guess its an overheat alarm. What is odd is that it has come on imediatly after starting the engine and with the key on and the motor not rinning it sounds. I can run it for days with no issue but then it will start again. I do see the constant stream of water out the back and the motor is still running great.<br /> I do intend to replace the water pump as its the original and the screens in the water intake are gone. Is it possible I am picking up some debris in the system. And is the water coming out the little hole in the engine indicitave of proper cooling? Thanks Bob

 

[Goodoleboy]

Re: 86 50 HP Evinrude alarm

Sounds like your overtemp sencor is shorted to ground. Thats what its suposed to do when the engine has overheated. But if it does it when the motor is cold then its shorted out.<br /><br />The telltale water does not curciulate through the engine block. it comes up straight from the lake. It just shows wheither your water pump is pumping or not. <br /><br />The temp sencor wire is the tan one comeing off the top of the motor head. <br /><br />Sometimes the short can take place inside the control box. Idd check for shortage their first before repacing the sensor.<br /><br />Good luck

 

[umblecumbuz]

Re: 86 50 HP Evinrude alarm

Goodoleboy tells you:<br />The telltale water does not curciulate through the engine block. it comes up straight from the lake. It just shows wheither your water pump is pumping or not.

I'd question that bit. The tell-tale is water that exits the motor after it has been through the block. <br /><br />No point having a tell-tale otherwise! You need to know if water is circulating. You don't need to know if it's just being picked up from the lake and dumped straight back again.

 

[Goodoleboy]

Re: 86 50 HP Evinrude alarm

Ive got a service manual for my 87 40 horse. And looking at the water curculation diagram. <br /><br />It shows in comeing water as blue and water after it passes through the therostat as red and back down the midsection and exit through the prop.<br /><br />Not all water taken in by the water pump goes out the telltale. Part goes through the engine block and part out the telltale.<br /><br />Its a pressure and resisants thing. If the telltale was to large an opening it would all exit their.<br /><br />Check the water temp exiting the telltale with your hand. It never changes temp but very little.<br /><br />Iam not trying to argue with anyone. But thats how I inturpert the drawing.<br /><br />And Ive held my hand in the telltale of my motor lots of times while ideling on the muffs.<br /><br />Just notice how quick water exits the telltale when you start your motor. It begins within 2 or 3 seconds.<br /><br />If it had to weight for the thremosat to open it would take a minute or more. <br /><br />And it would be very hot.

 

[njbob]

Re: 86 50 HP Evinrude alarm

I have just purchased a water pump and intake screens, I figure the WP is 20 years old can't hurt to try that. I also have read that this constant on alarm can be a fuel restriction. I have no idea what is meant by that, the hose? Hopefully I can change the WP myself I just got to figure out how to deal with the shifter. The last one I did was an older 3 cyl electric shift. I don't have the patience like I used to though. My next step would be to diconnect the overheat sensor see if it stops. Also I can borrow one of those infrared temp sensing guns. Anyone know what the right temp should be? Thanks Bob

 

[Goodoleboy]

Re: 86 50 HP Evinrude alarm

Bob....The service manual for my 87 40 horse says temp should not execede 163 degres. Intake water water shoud not be below 80 degres for the test.<br /><br />Same test says motor should not run below 125 at idel after sufecent warm up time.<br /><br />These test are being done with melt sticks. on the head.