1963-1973 Mercruiser all Engines and Drives Service Manual Books 1 and 2, Page 34Get this manual

1963-1973 Mercruiser all Engines and Drives Service Manual Books 1 and 2, Page 34

TUNE UP DESCRIPTION This ction outl ine procedu re to fo llow wh perform ing r1ealn tuneup on rCruise Marine Engi nes and
co mprcs ion of eac cyLinderCompr on hould read indi etted in tuncuppecifiet lions' ct ion 8Variation be tween highest and
lowest readin cylinders shoul be less than 20 Ibs( 1.4kg 6If one or more cylinder read low or un even inj ect tablespoon
of engine oil op piston thru park plug portCrank engine seve r.J lim and recheck mpre ion7 Checking results: aIf compression
increases, but does not necessaril reach nonnal, rin gs ar worn bIf co mpression do not improve, valves are icking or seating
poorlycIf adjacent cy linders indicate lo co mp ressio and not increa compressionthe cause inj ting il may head gasket leak
betwee cylinders with resulting engine coolan andCK" oil in ylind ers SPARK PLUGS CONV ENT IONAL TYPE numb as ted und er
sp cifications2Prior to installing used plugsfil en eo-od flat and adjust gap to setting with round fee ga uge(Figure _)
3Pri to in talJin P' plu gs, adjus gap to setti ng listed in specificatio ns, with round feeler gauge(FiguT 2) 4Wi pe plug