Knocking noise in the area of my coupler??

[jackson269]

Hey guys. I was on the water yesterday and the boat was acting sluggish and revving. I would be at 3000rpm and it felt like it was dragging and then it would rev up to 3500rpm and sound like its old self. I am figuring that I some water in the fuel. So I was about 10 miles out and decided it was best to turn around and head in and inspect from shore. I got into the harbor no wake zone, throttled down and started to get a loud clanking, knocking from the area of the coupler. What in the heck is that from??? I am going to try greasing the grease points to see if that helps. Please let me know if anyone has experienced this. Thanks

 

[dvx216]

water shutters in your exhaust pipe below rubber coupling will clank when idling when the rubber wears off of them. When you speed up they stay open and don't clatter could be that

 

[Bob & Sue]

I had a coupler spline strip out 5 years ago in a no wake zone docking for fuel, when it happened at first it sounded like what you described, when the spline finally stripped completely it was just a whirring sound as the drive shaft spun around in it. From what described 3000 rpm jumping up to 3500 rpm sounds like it could be the rubber coupler slipping letting it rev up. Coming down the no wake zone it may have started tearing apart.
Did you smell any hot rubber?
Did it make the noise shifting in & out of gear or was it a steady noise in gear and in neutral?
Does it sound like it could be u-joints?

If it's a constant sound I'd tie up tight to the dock and have someone put it in gear to see if the drive line is rotating & find out where the sound is coming from.

It could be the flappers making the noise but that wouldn't have any effect on the rpm's.

Maybe someone will have some other troubleshooting tips.

 

[jackson269]

There is no smell at all. I don't think its ever been greased so I am doing that today. When I docked, I had no issue going from reverse to forward. It acted normally except for the sound. The revving is still an unknown. I am changing my fuel filter today.

 

[jackson269]

Greased the coupler today and changed the fuel filter. The sound has completely stopped. I took the boat out for a run and it still is doing the revving thing.... starting to think its either prop slip or something with the lower

 

[Nauti1]

Put a line with a paint pen, on the coupler on down to the shaft. Run it around for a while and see it the line is separated. If it is, then you'll know it's the coupler.


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[jackson269]

So after using gum out products and running the heck out of it over the weekend, the motor is running great once again.