1991 Mecruiser alph drive knocking nooise

[jallen100]

I just bought a 91 Thompson 21.5' with a Mercruiser 4.3 Alpha and I have a bad knocking noise. Its not from the engine but it almost sounds like a rod knocking. It went away as I trimmed the boat but then cam back. The boat runs great but that noise is awful. Any ideas?????

 

[Don S]

Re: 1991 Mecruiser alph drive knocking nooise

Remove the outdrive and start it up and see if it's still knocking. Won't hurt anything to run it for 15 seconds or so to see what happens.

 

[Bondo]

Re: 1991 Mecruiser alph drive knocking nooise

Ayuh,... Pull the drive, 'n try it, atleast you'll know which end is the Problem...

If it's the motor, rebuild or replace...

 

[jallen100]

Re: 1991 Mecruiser alph drive knocking nooise

Gimbal bearing was toast

 

[Don S]

Re: 1991 Mecruiser alph drive knocking nooise

If the gimbal bearing was bad, I would bet you have a lot of other problems also. Like water in the bellows ?????

 

[jallen100]

Re: 1991 Mecruiser alph drive knocking nooise

If the gimbal bearing was bad, I would bet you have a lot of other problems also. Like water in the bellows ?????

Yep and I had to replace the bellows also.