Mercruiser 3.0 knocking noise

tony.lewis411 said:
The oil pressure seems ok but does fluctuate. At low idle the pressure will drop, higher idle it will increase. I've thought that was odd but it's been that way for some time now. I've been told it could be a main bearing..
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Main bearings will not knock - only connecting rod bearings. If any of the crankshaft bearings failed oil pressure would be significantly low.
 
Lazy Daze said:
Are you sure it's not from high trim angles? Meaning, coming from the driveshaft universal joint.
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This happens no matter what angle the trim is set to. The video I posted is with the trim down.
 
Timing chain slapping inside the cover it doesn't sound like a rod knock to me but it could be I don't know I hope you have a good luck with it
 
It sounds too tinny to be wrist pins to me it sounds like something is just loose but it is with every engine revolution. I must have watched it 20 times it does not sound internal it sounds like something hitting a pulley or the bell housing or something like that
 
I have received a lot of suggestions that it's something external like a pulley or a U-joint so I will be looking into these this weekend. I also had a recommendation to check the engine mounts. I want to thank you all for your suggestions and time. I will let everyone know what I find
 
I don't know your skill set, but removing the drive and running the engine with a hose stuck in the hole will negate the driveshaft as a variable. Roughly speaking, about 30 minutes to pull it.
 
With the way it's shaking, I would do a compression check on the cyl's.

Sounds like a piston trying to escape.
 
I did notice all the shaking but it's such a short video that's why I had to watch it so many times it's just hard to get a fix on it
 
I just watched it another 20 times and the pulley to the furthest right side of the video it looks like it's not spinning as fast as the other two pulleys are and I can't tell what it is because I can't see it long enough. It just doesn't sound like any rod knock that I've heard in any of my engines that I broke or blown up how long has this been like this and has it been running like this for a while I thought he said it did
 
So this happened after you replaced the exhaust manifold and gasket is when this noise started That's got to be a clue right there
 
So I went back and reread everything he said it's been running like that for 10 years if I'm reading that right there's no way a motor could run that long with a rod knock not 10 years My missing something. Please let me know this one is a real shocker
 
On my Samsung s21 I had to download the file then extract it and then it asked me what I wanted to play it on video player or Google so I was able to view the video
 
Are they a gear to gear instead of timing chain engine? I believe they are. I am thinking that is your noise.
 
Sorry for the delay here. The weather has been a bit crazy in Spokane. Little rain, snow cold etc. This weekend will be nice and I will dive in
 
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