[Seabass86]

Hi lad, I have the engine above and have noticed that if I idle for abit that it'll stop pumping water and the alarm will start going off. No problem when moving just going very slow or idle. Any help would be great thanks.

 

[Clinker]

What age is it?

 

[Seabass86]

What age is it?

2005

 

[Seabass86]

What age is it?

 

[Clinker]

the 99 - 08 generation was Yamaha powerhead on a Mercury leg and cooling problems are notorious. There's a rubber grommet between the waterways on the powerhead and the leg. A mismatch of Yamaha and Mercury metals causes electrolytic corrosion which in turn closes the rubber grommet up and restricts the waterway or closes it up altogether - cheap in parts to fix, expensive in labour or your own DIY time.
But before pulling the powerhead (it's probably already been done once or twice on a 15 year old engine), worth checking the impeller is OK.