Merc Manifold/riser water leak

[SeaRayViking]

my year 2000 4,3litre Merc with only 100 hours on it suddenly scared me the other day as i detected a bit of water at one of the mans/risers after en little run in the bay.
It's been a trailer boat for eight years and has always been flushed after sailing salt waters. And serviced every winther.
But now it's in the water - permanently - and it's salt...

She runs beautifully and starts within a second. Also even if its been a week or two since last run.

But this is new - i hope it's not that bad. I hope it's just a question of replacing the gasket?

sorry the pic's not that good, but one can see the water.

What would you suggest that i do from here?
thnx

 

[JustJason]

Re: Merc Manifold/riser water leak

Hours can be irrelevent and misleading. A leak, is a leak, is a leak. Your lucky you caught it. The riser needs to be pulled off and the water jacket needs to be inspected. If its clogged it needs to be replaced. If the sealing surfaces have rotted and there is less than 1/4 inch of clean metal, they need to be replaced.
Risers need to be replaced in pairs as well.