Fresh Water Cooling System Install For Older Nautiques

[EchoLodge]

Trying to educate myself on installing a fresh water cooling system. I have seen kit prices from 500-800. Any suggestions or tips would be appreciated.

[inboardsonly]

Get the PCM Kit.

Some of the PCM kits have the heat exchanger down low. I think
that is for a fuel injected (Tuned Port style of engine). It mounts on the
starboard side below the manifold. Makes changing spark plugs, the starter and the blower a real joy.

Some have it above the intake manifold (Carbureted model.)

Would take about 5 or 6 hours to do the install.

Remove thermostat housing and replace with new.
Install heat exhanger, install header tank, re-route some hoses,
cut some hoses, remove shower kit from boat if you have one, fill with
antifreeze.

The PCM kit gives you a FWC block, but raw water cooled manifolds and
risers.

There might be other kits available, but I would stick with the PCM, they are finished nicely, and are engineered for the engine/boat combination.

just my .02

IO

[EchoLodge]

Thanks!

[DavidF]

FWIW: All FWC marine engines (or kits) use raw water for the heat exchanger and exhaust manifolds. There is no other way to do it. Only draw back is corrosion to the exhaust manifolds if not flushed after salt water use. But, not really hard or relatively expensive to replace on a regular basis.

[EchoLodge]

So there is no real advantage I am learning. I do have a flush kit installed. I know salt is like cancer and it will be hard to make the decision. I live 30 minutes from Long Beach Marina in SoCal but I drive 4 hours to ski on the Colorado River! If gas keeps going up I may start foiling in the salt to keep my hobby alive! How often would the manifolds have to be replaced with skiing 4 times a month?

[Bob's2001]

If you flush them every time they should last for many years. I just replaced one and my boat is 22 years old.

Bob
83 SN 2001
Monster tower

[inboardsonly]

There are a few advantages to running FWC.
Engine can run at 180 instead of 140. If you run a raw water
cooled engine at 180, it will salt up real quick, or overheat.
Engines like running at the higher temp.

The manifolds will probably last about 5-6 years, with a flush kit.
The engine will last a lot longer if it has the FWC. Engines cost more
to replace than manifolds and risers.

Your heater will last a lot longer, and will give off waaay more heat.
See above...

There are manifolds out there (Mercruiser and some Osco Manifolds) That allow you to have the coolant go in and out of them. There is a block off plate between it and the riser, and then the riser gets the raw water from the heat exchanger. Some risers are available in SS or Aluminum, and that will also extend their life.

The downside to this system is all of the hoses necessary to make it work.

Cleaner looking install if just the block is FWC. Install a flush kit, and
use it! If I was going to use my boat in the salt, I would do the FWC.
Especially for resale.

Then there is the question of the trailer, but that is a whole 'nother story.

[EchoLodge]

If you flush them every time they should last for many years. I just replaced one and my boat is 22 years old.

Bob
83 SN 2001
Monster tower

Finally got around to changing mine out. I have been running it in salt for the last 5 years. The boat is 20 years old (1200 hours) and all the bolts came off the exhaust manifolds. One bolt was rusted on the risers but since I was replacing both manifolds and risers it was not an issue. I probably could have made them last longer had I replaced the riser gasket when they first started leaking.