Quote:
Originally Posted by Dave R
There's a temperature gauge and an audio alarm for overheating. If the engine is being pushed hard when the supply is interrupted, the rubber hoses in the wet exhaust system can get hot enough to melt and smoke (without actually failing) before the alarm goes off. That's what typically causes the smoke. The hose has to be marine-rated (typically SAE J2006 standard) which defines temperature resistance and flammability, among other things, so the chances of a fire from this situation are not as bad as you'd think.
Another cause of smoke might be the engine's serpentine belt heating up due to a stalled water pump pulley.
I'm surprised that the manifolds needed replacement from a single overheat situation. Non-catalyst manifolds usually survive that kind of abuse without issues and the innards of all catalytic converters can easily withstand absurdly high temperatures since they require them to operate. I wonder if they were swapped for purely cosmetic reasons. Malibu puts a lot of "bling" on their boats, so perhaps the engines are dressed up as well.
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Thanks for the info.
I'm with you about the manifolds, and this is why I asked the question about alarm systems. If they got that hot and had to be replaced, then the alarm system must have gone off prior to destroying them and the engine should have been shut down somehow. I'm going with your theory about replacing them for cosmetic reasons only.