Knocking 3.0L Mercury

[STC]

2003 Bayliner. Idle and in gear the engine has a loud knoking sound. Took it to the dealer. They confirmed it is loud, but that is was normal for this engine. You can hear the knocking when standing on shore over 100 yards away. No other I/O like it sounds this way. There is no loss of performance, it just sound very bad. Suggestions?

 

[Bt Doctur]

Re: Knocking 3.0L Mercury

there should be NO knocking sounds from a motor or drive. there is a "ratcheting " sound when shifting into gear but not that loud.

 

[searay3]

Re: Knocking 3.0L Mercury

You will have to pull the drive and have a look. Check the u-joints/bellows/gimble, condition of drive oil. If all looks good there, put a garden hose in the water hole where the drive mates up and start it. This will help you isolate whether the noise is on the drive or in the motor.

 

[Reel Poor]

Re: Knocking 3.0L Mercury

I would check engine and drive oil for metal contamination. In bright sunlight may show metel flake content in oil. Like searay said if you can't determin if the knock is in the engine or drive, remove the drive and start it up. No knock = noise in drive. Still knocks = noise in engine.

 

[DHPMARINE]

Re: Knocking 3.0L Mercury

I'd request a service rep from Mercruiser.It is his job to do this,even though you may be out of any warranty.Mercruiser wants their products running 100%.

Not my business,but did you take it to the dealer where you bought the boat? Just hits me wrong for a dealer to say loud nocking is normal.

DHP

 

[Don S]

Re: Knocking 3.0L Mercury

Merc's not going to send a rep out to listen to it until there has been several talks with a local Mercruiser dealer. Even if it's still under warranty.
I can't see any mechanic saying a knock (as described) could be normal.
I have also had customers complaining of noises where they thought the engine was going to explode only to find the alternator belt coming apart and hitting the engine.

 

[4poco]

Re: Knocking 3.0L Mercury

I have a 3.0L mercriuser, 2005 bayliner and asked the same question.
Took to dealer and they also told me that this was normal. If you listen real close, i think you will find its not the engine, but coming from the back somewhere. I have learned to live with it and ussume its just a bayliner thing! It doesnt seem normal to me, but im not a mercriuser mech. They also told me that this was an industrail engine and is made for high rpm's. Some are louder than others.... go figure !!

 

[Bt Doctur]

Re: Knocking 3.0L Mercury

It`s not normal.where do these dealer mech.`s come up with these answers?

 

[STC]

Re: Knocking 3.0L Mercury

2003 Bayliner. Idle and in gear the engine has a loud knoking sound. Took it to the dealer. They confirmed it is loud, but that is was normal for this engine. You can hear the knocking when standing on shore over 100 yards away. No other I/O like it sounds this way. There is no loss of performance, it just sound very bad. Suggestions?

 

[STC]

Re: Knocking 3.0L Mercury

Thanks for the advise. I'm scheduled to take it back in to the dealer I bought it from. It's too loud to live with. I'm hope to get the boat on the water to show just how loud it is. It always seems louder on the water since the exhaust is muffled under water.

 

[ozziebob]

Re: Knocking 3.0L Mercury

I have worked on 3lt engines before in some bayliner boats and have not heard this noise you speak of. However may be a different model boat. The noise may just be harmonic noise but I dought it very much If I were you I would go to www.mercurymarine.com and go to the contact us part of the page. It allows you to leave your details and get a responce from mercury themselves. Tell them the dealer thinks the noise is normal but you belive it sounds to harsh. At least then you will have piece of mind. They have a record of it should something happen down the track.