Volvo penta 3.0L 4 cylinder makes rattling noise??

[Walleye2416]

I have a 2002 Volvo penta 3.0L I/O system. I bought it from a guy who hardly used it and kept it in the garage heated. I have owned it for 2 years now and have also taken great care of it. I went on a weekend fishing trip and was driving the boat around like normal, and after trolling around for a bit I turned on the engine and heard a rattling sound coming from deep inside the engine. I never heard it before and it's always ran smooth until just now. After I heard the rattle noise I put it in forward drive just to see how it sounded under load and the same rattle noise was there. It's not super loud but something sounds wrong, and it sounds like it's coming from one of the cylinders.

Any ideas??!

 

[alldodge]

Noises are real hard to determine where you at and even harder over the net. Use a stick, dowel rod, broom stick cut short and place against your ear. Then touch the other end around different places to see if you can locate what area its coming from.

Check drive lube level and pull the drain plug a bit to see if any water has made it in

 

[Scott Danforth]

could be detonation. does it sound like marbles running around in the motor....if so, how old is your fuel. how is your timing?

detonation is the sound of pre-ignition or more importantly, your motor eating bits of itself

 

[Walleye2416]

I will try the broom stick idea to see how close I can narrow down the source. BUT the sound doesnt sound like marbles, it sounds more like there is a high pitched chime bell (like metal clinking). And its a very high pitched noise. My fuel is great, like I said, I had just went full throttle 30 minutes before this happened and it ran smooth and no issues.

 

[alldodge]

With a high pitch noise I would check your gear lube first