Johnson 175 severe knocking HELP!

[pbguy420]

So I was out in queens creek today and we definitely bumped a sandbar or three, nothing incredibly hard maybe going 15 mph... Anyways on the way back after running at WOT for 15 min or so and sounding great the motor acted as if we hit bottom with a knocking/wobbling sound you get when your lower unit is just touching bottom at speed.... Thing is- we were in 14 ft of water, it wasn't the bottom it was something in the motor....

Also noticed that it only did it over 3000 rpm. Under 3000 it was fine but once I rev beyond that it knocks and wobbles like crazy..

Wierd thing is, we started limping back to shell Rock at idle speed and just to see what's up I tried to open up the throttle again and it acted fine and we drove all the way back... What the heck?!

No grinding, shearing or actual breaking sound just a fast pace knock that sounds the motor is bumping bottom

[Juan]

I'd be guessing at what caused the knock but I had a 200 h.p. Mariner on bass boat once that threw a connecting rod and sounded like that. It ran fine at idle or a little over but when the other cylinders kicked in at higher rpms, it knocked.
What ever it is/was.....it didn't fix itself so I'd take it by the shop and have it checked out before it gets worse.

[pbguy420]

It's not a thrown rod bc the noise went away, my buddy is an evinrude tech and wants to take a look at it this weekend, now it knocks a bit In reverse but not in forward. He thinks I might have bumped the gear linkage out of whack

[BoutTime]

Sounds Like it may be the lower unit..
IF it is, I have a Johnson V-6 lower unit that I think will fit your 175 should you be interested..??

[freezerfiller]

I'd start by spinning the prop and looking to see if it or the shaft that it seats on is warped. Alot of times a bent prop will feel bad at certain rpms, and smooth out at others, much like a tire out of balance. But it will eventually tear seals up so it needs to be fixed. Hopefully its just a prop or a shaft and not the engine. Good luck