1999 ox66 200 ticking and knock

[castnblast77]

Ticking noise comes and goes after motor is warm. Its a real light tick that sounds like a lifter or injector and is a bit sparatic and gets faster with higher rpms and sometimes goes away and some days it doesn't do it at all. Wristpin?? O2 sensor?? Injectors??
Next is the knock/rattle. When coming off high rpms to fast it does this. No other times.
Other than these issues the motor runs outstanding.
Any help/input is greatly appreciated.
Thanks

[rodbolt17]

the ticking could quite possibly be the O2 sensor draw tube is clogged.
the rattle could be the prop rotating backwards if you throttle down to fast.

[Dufrsp31]

I have the same engine with the same symptoms. I pulled the draw tube and it was pretty much clear through the center hole. The outside however was full of carbon so that it didn't look like a "dog bone" or "dumbbell" anymore. One side of the draw tube was shiny, while the other side was black. I cleaned it and reinstalled. The O2 sensor tip was clean and no holes were blocked. I installed new gaskets and put it back together. I left for work the next day and did not have a chance to go run the boat. I'm at work offshore for the next 14 days.

Do you think cleaning the carbon off the outside did anything to fix it or because one side was shiny, I need to replace it with a new draw tube (joint 65L-11353-00-00)?

[99yam40]

I am no expert, but if it is rattling around because of too much clearance , cleaning carbon out would not tighten it back up

[Dufrsp31]

That's what I was thinking also now that I've had a chance to read more. Then I found this thread on THT forum which shows a picture of his draw tube (joint) that is shiny on one side. Mine was similar, except the carbon was solid all the way across the dumbbell. Apparently he got it to stop ticking/knocking after he cleaned it.

https://www.thehulltruth.com/boating...ing-sound.html

I was going to order new joints online being I'm stuck offshore, but I think I'll wait to run it before buying more parts.