merc 50 4 stroke alarm sounds!

[tamarackcove]

I have a 1995 mercury 4 stroke motor. When I troll for a while the alarm sounds. If I stop the motor and restart, it goes away, but comes back on in about two or three minutes.If I just crack the throttle to raise the rpm's a 100-200 higher, it stays off on the restart.<br /><br />Is this a faulty sensor or a problem with the water pump/oil pressure? The "spitter" pumps a steady, srong stream of water and the motor does not seem to be overheating.<br /><br />I bought this motor and boat this past winter and the motor runs strong and pushed the 18' Lund Pike ang just fine. There is no power loss, but this stymies me. I could take it in to the dealer, but I hate having par aytaycove@yahoo.com ts replaced that do not have to be, just to "try" to find where the problem lies.<br /><br />Thanks for any help you guys/gals can give me.<br /><br />Art

 

[orca]

Re: merc 50 4 stroke alarm sounds!

The alarm can sound if the motor is running hot or if the oil pressure drops.<br />Run the motor with the cover off, when the alarm sounds then put your hand on the exhust cover, if you cannot rest your hand for a few seconds then the motor is overheating.<br />also< when was you engine oil last changed

 

[tamarackcove]

Re: merc 50 4 stroke alarm sounds!

I thought perhaps it would be the oil, but I changes the oil and filter. I put 20-50 oil in it thinking that perhaps gthe oil was thinning down. The alarm still went off!!<br /><br />I will hook a muff up to it and pull the cover to see if the engine is overheating. There are no signs of it, as the motor pull fine, jumps the boat up on plane and runs super strong.<br /><br />Is there a thermostat on this engine?? If so I could pull it and check to see if it's opening.<br /><br />Like I said, the "spitter" is working fine, but that does not mean that water is getting around the cylinders to cool them.<br /><br />I will replace the water pump and see how the old one looks when I pull it. <br /><br />Hey, thanks alot for the response and ideas!!

 

[orca]

Re: merc 50 4 stroke alarm sounds!

Good idea about the thermostat.<br />Tou will finf theThermostat is on the exhust cover plate Port side of the motor.<br />Let us know how you get on.