REVISED GALLERY PLUG NEW LARGER PLUG WITH 'O' RING

A SECOND TYPE GALLERY PLUG IS BEING PHASED INTO PRODUCTION JANUARY, 1985 FOR ALL HT4100 ENGINES. THE NEW TYPE UTILIZES A MACHINED BOSS ON THE BLOCK TO FACILITATE A LARGER PLUG FITTED WITH AN O'RING SEAL (SEE FIGURE 1). THE OTHER PLUGS ON THE LONGITUDINAL ENGINE HAVE NOT BEEN CHANGED. THE NEW PLUG MAY BE REMOVED BY USING A 12MM ALLEN WRENCH, AND MAY ONLY BE USED ON NEW ENGINE BLOCKS. THE SERVICE PART NUMBERS ARE AS FOLLOWS: O-RING SEAL P/N 1628828 NEW GALLERY PLUG P/N 1628827 WHEN INSTALLING THE NEW PLUG, TIGHTEN TO 42 N.M (31 FT. LBS.). NOTE: FIRST AND SECOND TYPE PLUGS ARE NOT INTERCHANGEABLE. USE OF THE INCORRECT PLUG WILL DAMAGE THE CRANKCASE THREAD.

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