Volvo Penta 4.3l noise front engine

[chuongnino]

Recently my boat has been making a knocking noise. I took the belts off and try rotate the pulleys one by one. The water circulation pump was making just a little noise and super rusty so I jumped into the conclusion it was the cause. I replaced it with a new one and still the noise is there. I took the belts off trying to determine where is the noise again. With all belts off, the crankshaft/harmonic balancer was making that noise. Could someone help me what should I test/do next? I am trying not to break the bank bringing it to a shop if I can fix this myself. Thank you in advance.

The video shows the noise for your reference. With all belts off the noise is still the same. I run the engine on muff and within short amount of time only.

 

[chuongnino]

Video with belts off

 

[Tyger23]

That sounds a lot like rod knock to me. With the noise coming from the crank/balancer area, its a pretty good guess that your engine has some serious issues. If you're not comfortable with engine work - then it's time to take it to a good shop.

 

[Jeepster04]

Sounds like the balancer is rubbing on something. Have you tried looking on the back side of the balancer to see if it could be rubbing on something? That does not sound like rod knock.

 

[cptbill]

Yea I'd say check your clearances on the harmonic bal. and also I don't know what year that is but some have a tensioner for the timing chain and it could be that

 

[Jeepster04]

Yea I'd say check your clearances on the harmonic bal. and also I don't know what year that is but some have a tensioner for the timing chain and it could be that

It does sound a little like a chain slapping.

 

[Lou C]

Get a mechanic's stethoscope it will make the diagnosis much easier because you will be able to localize the sound, just be careful around rotating machinery.