Mercury 4 Stroke overheats at idle????

[Bass-man]

I have a 2004 Mercury 50 4 stroke EFI with less the 5 hours on it. If I idle for more then 2-3 minutes the overheat warning horns sounds off. I notice that the water tell is not squirting out a steady stream of water either at idle either. If I shift into gear and get the rpms up a little then the overheat alarm goes off and the water tell has a steady stream of water again. I was told this is normal for mercury 4 strokes but it does not seem normal to me. Anyone has suggestion or comments on this? Thanks

 

[Dunaruna]

Re: Mercury 4 Stroke overheats at idle????

I have the same motor, it pees strongly from the getgo (cold idle).<br /><br />You have a blockage. Back flush it (a garden hose will 'screw' into the pee hole outlet). See what comes out. You can do this without running the motor.<br /><br />If that don't fix it, take her back to the dealer for a pump inspection.<br /><br />Bob.

 

[WillyBWright]

Re: Mercury 4 Stroke overheats at idle????

Age doesn't matter. Water pump impellers should be replaced annually according to manufacturers. Every 3 is more realistic. But if it has ever been starved of water or ingested sand, service is usually required.

 

[Dunaruna]

Re: Mercury 4 Stroke overheats at idle????

The manual specifically says every three years not withstanding foreign ingestion.

 

[Bass-man]

Re: Mercury 4 Stroke overheats at idle????

How long do you run the water when backflushing it? If no debri comes out and there is a steady flow of water then what should I do?

 

[Bass-man]

Re: Mercury 4 Stroke overheats at idle????

I did the backflush in my driveway today. After the backfulsh I hooked up the regular flush ears at the water inlet and there is no water coming out of the water tell at idle, it barely drips out? But when I am on the lake it comes out a steady stream as long as I am not idling. What does this mean?

 

[Dunaruna]

Re: Mercury 4 Stroke overheats at idle????

[colour=blue]Pump is bad.[ /colour ]