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496 MerCruiser 8.1 with Chirping sound at rear of engine

M

Marchman

New member
I have 2006 MerCruiser 496 8.1 with Bravo III with 420 hours. A "chirping" sound has developed somewhere at the rear of the engine when warm. Chirp is most noticeable at idle, overshadowed by engine noise at higher speeds. Engine bilge had previously flooded to cockpit floor level. My normal mechanic says he has never seen / heard of this. His theory is that coupling got wet, rusted, and is now rubbing causing the chirp. Why only when warm? I will appreciate any ideas. Thank you! Marchman, Apollo Beach Florida
 
Unusual noises are a warning that something isn't right. Ignoring it won't make it go away. Your action at this point is to get the drive off, engine out and have a good hard eyeball at everything. You don't want to get stranded out there.
 
I am planning to remove the drive. Pulling the engine is a major job I really hope to avoid. Just yesterday I learned (page 61 of owner's manual) that there are two grease fittings on back of the engine coupling. Any other ideas will be appreciated.
 
Get a automotive stethascope and pinpoint the location of the noise first then post what you find.

There are to many unkowns for a simple answer.

Otherwise have a certified mechanic take a look.
 
Marchman - I can only get to one of those grease fitting on the engine coupler. Also, there maybe another grease fitting (gimble) outside at the transom where the out drive penetrates the boat. Its got a cap on it and its well camouflaged. All these fitting get 5 grease pumps per season.
 
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