1996 mercury half power

[Kern57]

First post on here but, I have a 1996 mercury efi 150 hp
When I turn the key on I goes “beep” beep beep beep the boat will run for about 10 mins full speed and then the boat cuts to half power, have replace thermostats, water proper and heat sensor and sender any info will be great thank you

 

[Faztbullet]

When it fails check to see if you have spark on all plugs

 

[Kern57]

Middle 2 were dirty

 

[Faztbullet]

Need to check spark when it happens...could be a switchbox or one side of stator dropping out. Also could be a bad rectifier causing stator to get hot.

 

[MPrimeaux]

4 beeps is a low oil alarm I THINK. I think it's 4 beeps every 2 minutes and that will put it into guardian mode. If it has oil, you can check continuity on the two wires going to the float sensor. It should be closed. If it's open and full of oil, the float sensor may be bad. I think you have to replace the whole reservoir if that's the case. I'm not an expert, but my buddy just went through that.

P.S. I just read that 4 beeps every 2 minutes can also be water in fuel alarm. I remember him cleaning out, then replacing some sort of water separator in the fuel system too. I think it's located on the port side of the engine kinda forward.

 

[Dukedog]

what Faz says...

no guardian mode.. beeps when key is turned on are "self check" beeps that let you know oiler alarms are workin'.. none of which has anything ta do with loss of power.. only two types of alarm on your motor.. a constant continuous beep is over heat and a oscillating beep, beep,beep,beep,beep etc is oiler problem or water in fuel...

 

[Dukedog]

one other thing might add.. when power drops pump fuel blub if its soft.. possible fuel delivery problem also..

 

[Kern57]

Actually I was hearing it wrong when key is turned onto run it goes beep beep beep with the first beep being slightly longer and two faster beeps right after

 

[Dukedog]

Actually I was hearing it wrong when key is turned onto run it goes beep beep beep with the first beep being slightly longer and two faster beeps right after

:encouragement: