GOOD NEWS. . . . The PICTURE UPLOAD FUNCTION IS WORKING !!! The tech folks at the parent company have been able to remedy the issue. You can upload pictures once again. Thank you for your patience.
Why are the exhaust manifolds cooled on I/O's and inboards? Is it to cool the gases or just to keep the heat down as much as possible in the engine compartment?
Technically they arent cooled, thats just the way the water exits the system. However cooling them has many benefits, the main benefit of which is lower engine compartment temperatures. This helps keep vapor locking away. People tend to forget a boat's engine compartment is pretty closed and not like a car where air is always moving around it.
Yes it does help cool exhaust gases, thats why we can use rubber exhaust components, it also helps reduce exhaust noise also, ever hear one of those big offshore's with dry exhaust, super loud, and for the reasons diesel comments on.
My schooling says that exhaust systems are indeed 'cooled'. The whole point of the wet exhaust system is to cool the exhaust components - specifically to allow the exhaust pipe to go through various structural parts of the boat (like the transom) without causing a fire.<br /><br />Dry exhaust can also be used, but has it's own problems for the consumer as well as the manufacturer. <br /><br />For references look up:<br />a. Title 46 CFR 58.10<br />b. Title 46 CFR 182.430<br />c. Title 46 CFR 177.405<br />d. Title 46 CFR 177.970<br />c. ABYC, Project P-1
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