Spark plug part# for 89' Merc 5.0L 305 200HP

[Fordiesel69]

89 Merc 305ci 200HP

Could someone provide the part# from the book. I need to verfiy the NGK's in there are not too cold. I do not trust the automotive part#

 

[Fun Times]

Re: Spark plug part# for 89' Merc 5.0L 305 200HP

Spark Plug Type AC-MR43T/Champion RV8C/NGK BR6FS.
Spark Plug Gap .035 In. (0.9mm) Timing (At Idle RPM) 8 BTDC.

Your old Merc part number 33-59571 (NGK BR6FS) is now Superseded to 898264001 (AC SPRK PLUG) MSRP: $3.58 each.

 

[Fordiesel69]

Re: Spark plug part# for 89' Merc 5.0L 305 200HP

BR6FS has a very short external body and most are suffering from external ceramic cracks. The AC MR43T looks more correct with a longer external body. They only had 4 in stock so we picked AC-MR44T. Engine runs like new now. Thanks to the fogging oil, it oil fouled some of the bad plugs with cracks. My friend had a surge / power loss last season and this was the cause.

 

[Fordiesel69]

Re: Spark plug part# for 89' Merc 5.0L 305 200HP

Not to mention their gaps were all .045 - 0.55, way out of spec.