1989 Carver Montego w/Volvo Penta AQ271c

[jrides55]

Hey, I'm looking for some advice on part of the cooling system on this engine. Where the raw water hose comes through the transom, it goes into a plastic fitting which runs into a black tube with a couple rubber hoses coming off of it and at the top it goes into the raw water hose which runs to the impeller. Sorry I don't have pictures.

Does anyone know what this black, vertical tube does? Is it possible that this tube could be plugged? I can't seem to find anything to help me identify this. Thanks!

[km1125]

Sounds like an oil cooler of some sort. Could be for engine oil or transmission fluid.

Yes, it could be plugged. You could remove the raw water hoses from each end and spray water though it backwards, or use a wet/dry vac on the "input" side to see what you might be able to suck out.

I'm guessing you're having some kind of overheating issue that you're trying to resolve? What have you done so far to investigate the issue?

[Viper]

If the raw water is coming through the transom, it'll be a sterndrive application, so as KM mentioned, it's likely the engine oil cooler. It's a heat exchanger designed to cool your engine oil. Yes this can clog with marine growth. A picture would definitely help identify the part you're talking about. Why are you asking, do you have a cooling issue?