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Thanks. Guess I better get a manual. This old Nissan runs real well.That info is listed in the Factory service manual, available from any dealer.
Part #: 003-21034-2
List Price (MSRP): $41.67
There is only one 8mm plug on the underside of the motor. Item 24 in this diagram:
View attachment 20161
Incidentally, the MFS 4/5/6 are all the same except for the carburetor. You can add 20% power by installing a 6 hp carb.