Bubbles in raw sea water exhaust

Mercruiser 454 (1986) fresh water cooled with heat exchanger. Port engine sea water exhaust has bubbles and starboard does not. Had old fuel which fouled port Qjet carburetor. Had carburetor rebuilt and bubbles seemed to stop. Ran for 1/2 hour. One week later started engine and bubbles are back, but the engine runs good. No oil or fuel in the exhaust, just bubbles that make the exhaust look whiteish and not clear like the starboard engine. Is it bad fuel, exhaust manifold, riser? Don't have any leaks. Any ideas or have you seen this before?

As long as the engine isn't running hot, you should be ok. Being as the exhaust mixes with the water, some bubbling is expected but it shouldn't last long.

If the engine runs hot, its likely you have an air leak in the suction side of the raw water system. Using clear hose can verify the existance of air (bubbles) in the cooling water. Of course, aerated cooling water doesn't work very well and its cause needs to be found and eliminated.

You may also try reposting on the Mercruiser Board

Thanks. I'll give it a look.

This is probably a long shot, but it's possible that your Palmolive Injection system is too "rich".
Try to lean it out!



Seriously though......, that is a strange one! Hmmmm.

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