Blocked saildrive leg....

[JEN-et-ROSS]

Launched our B38 on Saturday and motored to our mooring, a 2 hour trip that involves the delights of Cuan Sound.....
It soon became apparent that all was not well with the cooling system, anything over 2000rpm and the temperature would start to creep up...
All seemed stable at 1700 or less so we decided to carry on... As we motored along it was obvious that the raw water flow wasn't what it should be but the fresh water coolant was fine....
It turned out the blockage was in the saildrive leg so this would need to be dealt with afloat...
Turned out to be easy as we had one of those 12v 'fast' dinghy pumps and this I connected to the saildrive seacock and in seconds the blockage was blasted out...
Worth a try if anyone else ever has the same issue........

[SorinCT]

Backwash with fresh water or air blasting can do the trick. Reminder to all on the hard to seal up the leg (3 through holes and 1 bottom), fill with vinegar and soak for 1-2 days.

[Odysseus]

Vinegar does not do it, use hydrochloric or brick cleaner, to get calcium off.

See my  leaning exhaust cleaning photo.

Odysseus.

[SorinCT]

I guess it depends how much buildup you have. Vinegar did the job perfectly for me. While brick cleaner/hydrochloric acid is stronger, it also reacts with aluminum and may aggravate already corroded parts.
On the other hand, your picture shows cleaning of exhaust elbow, which has a combination of carbon residue (acidic) and calcium deposits. Exhaust components are regularly cleaned with high PH alkalis (carbon remover solutions), not strong acids.

[Jeffatoms]

Consider a jump over the side with hooka/scuba and pry out the shellfish that are possibly growing in the slots.  It would eliminate a cause.

[JEN-et-ROSS]

Consider a jump over the side with hooka/scuba and pry out the shellfish that are possibly growing in the slots.  It would eliminate a cause.

The problem with these saildrive legs isn't the vertical water inlet riser up the front of the leg, it's the 'dogleg' or 'S bend' under the gearbox, this cannot be cleaned/cleared manually...
So owners have to resort to high pressure water/air or a chemical solution to the problem..
I guess it's a design fault, one that some owners have solved by bypassing the saildrive leg inlet altogether, and obtain cooling water from a separate seacock....

[SorinCT]

The additional seacock is a peace-of-mind solution that can get you out of a jam. I don't see any significant downsides in having one fitted where possible.

[geoff]

Having just been out to the garage to check  the passage from the base of the leg is straight up through the division plate into the base of the gearbox .I clean mine every year on the scrubbing piles with a length of 10mm studding , just push it up and waggle about  [they don`t like it up em] Only the base of the gearbox is cooled. The leg is half oil and half water ,acting as a heat exchanger Geoff