DORaymond

We know that one of the products of combustion is water. When our CAR'S exhaust is cool we see alot of condensed water exiting the tailpipe until the exhaust is hot enough to boil the water off. Car exhaust always exits downward, so the water does not pool in the exhaust or run back into the heads.

On a marine engine the exhaust exits upward and is always cooled. Can marine exhaust be too cool?

I have been chasing what I think is a reversion problem for a while, but could too cool exhaust also cause trouble?

Didn't Mercruiser used to use the 4 hose manifold/riser system that had the spring loaded balls that would restrict the flow of water to keep the risers hot until enough pressure (rpm) would open them?

ljsmith1

The 4 hose riser system and spring loaded pressure balls were used on the 454 Mag Alpha (I have one). They slightly pressurize the system and reduce the flow to compensate for the lower volume pump in the Alpha drive.

There is no way that any marine engine exhaust would ever run 'too cool'. Combustion temps rise very fast, and cast manifolds absorb the heat very quickly. Your water problem may or may not be reversion. Do you have flappers on your tips? Are you hydrolocking? Is your motor running a high-lift cam? Do you have stock style, wet joint exhaust manifolds?

Water in a car muffler is caused by a number of things, but primarily the catalytic converter. Since 1981, three-way catalytic converters have been used in vehicle emission control systems in North America. A three-way catalytic converter has three simultaneous tasks:

Reduction of nitrogen oxides to nitrogen and oxygen: 2NOx → xO2 + N2
Oxidation of carbon monoxide to carbon dioxide: 2CO + O2 → 2CO2
Oxidation of unburnt hydrocarbons (HC) to carbon dioxide and water: CxH2x+2 + 2xO2 → xCO2 + 2xH2O

DORaymond

Here is the basic (very general) formula for the combustion of gasoline:

C8H18 + 12.5 O2 ---> 9 H2O + 8 CO2

As you can see, alot of it is water vapor.