Westerbeke 4-107 starting motor goes 'clunk'

[mesayousa4]

My 4-107 starter motor will occasionally 'clunk' when I turn the key. After making the clunk noise, there is a current surge until I switch off the key. Engine will start seemingly randomly about 1 in 4 times. Ideas?

[Celestialsailor]

Perhaps a worn bendix shaft on the starter. It may be jamming somehow holding the contacts of the bendix solenoid closed

[sww914]

I'd take it off and clean and lube the sliding parts as a first step.

[mesayousa4]

It is off and the sliding parts seem really well lubricated. I also found the part number, Lucas 26163 if that helps.

[bobconnie]

Bad bendix, or a bad Forward bearing !

[Celestialsailor]

Yup...the bendix itself is usually a sealed unit. Typically it is a spragg clutch if you know what that is. It allows rotation in one direction. They're pretty tight tolerance, so it could be that id the shaft and bearings are in good shape