Tip - replacing a Hitachi alternator on a Yanmar block

[Jeanneau 45.2]

Just had to swap out on my Yanmar 4JH3TE a faulty 80A Hitachi alternator for a "new to me" identical Hitachi OEM alternator taken off a forum member's engine as part of an upgrade to a Balmar system. Had big problems mounting the alternator on the boss ... not even a 0.001" clearance ... a miserable hour spent contorted in the engine compartment. HERE IS THE SECRET ... to allow for dimensional variances in the mounting boss and alternator hard points, there is a floating bushing pressed into the rear mounting ear of the Hitachi alternator. I assume a new in the box alternator has this bushing flush with the ear leaving clearance under the expectation that the bushing will move inward under bolt tension and assure alternator sheave alignment. However with a previously installed used alternator, the floating bushing is already moved inward and all clearance in the mounting saddle is lost. I finally figured out the issue and took a drift pin and moved the floating bushing outward (i.e. increasing the clearances around the saddle). Less than five minutes to mount the alternator.

[Charlie]

Thanks great tip. Will keep that in the memory banks