Mid 80's 4.3 LX Alpha strange shudder

[cwoodffr]

I have had this boat for about 5 years (21 ft Chriscraft built by Grew)
Runs very well. Only service has been regular seasonal stuff and new bellows and shift cables.

It has had a shudder when in gear just off idle for as long as I can remember. Anything higher and it is just fine and smooth. The shudder is enought that I can see the windshield frame jiggling. Under load and out of the hole and at any cruising speed it is smoooooth.

confuses me as if it were anything like prop or bearings etc wouldn't it just get worse at higher rpm?

thoughts?

 

[achris]

Re: Mid 80's 4.3 LX Alpha strange shudder

Simply answer.... 90? V6...

Inherently unbalanced. Yours is a Gen I block, no counter balance shaft. That's why they put massive fluid mounts on the engines, then GM put counter-balance shafts in them, but not until 1992 (they called it a Gen II block)....

If your problem is that bad, I'd look at the engine mounts, you may have one that's failed (lost fluid).

Chris.........

 

[cwoodffr]

Re: Mid 80's 4.3 LX Alpha strange shudder

Thanks for the fast reply!

is it easy to ident a bad mount visually?

 

[achris]

Re: Mid 80's 4.3 LX Alpha strange shudder

Don't know, never actually seen one....

Chris.........