1988 OMC 3.0 Clunking (May be Thunking) at High Speed

[JDusza]

Hi,
A friend has asked me about his OMC. It is experiencing what seems to be a random clunking at high speed and it is now creeping in at low speed.
He took me for as ride. It is not like an ignition or fuel misfire. The whole boat shakes. You can feel it through the frame. It doesn't appear to have a repetitive pattern. It just happens.
It would seem to be drive shaft or gear box related.
Any ideas?
Thanks,
J

 

[bruceb58]

It's the dog gears that are slipping. They are going to need to be replaced. This is normally caused by the lower shift cable out of adjustment. This is a very expensive repair.