Hi all at moment i have a problem with my boat not cooling correctly it steams instead of water coming out.I have the feed to a single holed rudder which i don,t think is feeding enough water so am going to try a transom mounted pipe feed but am wondering should i feed to the head then into the manifold cooler & out the boat or would you advise two seperate transom feeds one to the head and other to manifold?your comments are eagerly awaited.Darren

On my monos I plumb the water from the rudder to the cooling jackets bottom fitting (carb side) out the top fitting (exhaust side) to the exhaust mainfold then to the tune pipe fitting (if used) then out of the boat. I also remove the stock Zenoah fittings in the water jacket and drill them out because they are restricted at one end.

Mercury94 wrote:

Correct.

Also, if you're gonna add a water pickup...test with one pickup going to the engine only, and the other going to pipe only...I say this because often times it's the pipe's cooling system that causing the issues, either by blockage or ex pressure getting by the Orings. Once you find the problem, in 99% of the cases a single water source will suffice. Engine first, then to pipe. In very cold water situations (if that ever happens for you...it does for me) you can then reverse this to pre-heat the water before going to engine.

Hi Darren

I use a dual pick up from the rudder. The first circuit goes straight to the cylinder head jacket and out of the boat.

The second feeds first the manifold joint then the pipe cooling jacket. No problems so far for me with this set up.

The exit points for the water outlets are deliberately well apart so that I can see water exiting from both circuits when running the boat.

Here's a couple of photos to show my set up:

If you double click on the images you should be able to zoom in for finer detail:

Mercury94 that was my problem the nipples were restricting the flow of water,the holes are very small at the opposite end of the nipples and unless you had said i would never have guessed.Thanks Darren