Thanks for the link to the info on old chain saws. I saved that for future refference. I didn't find the pro mach 55 listed in there, but I don't have the serial number right here to look it up with.
What oil ratio should I be running in that old McCulloch? I used my Stihl 50:1 mix from my other saws to test it. I noticed that specs show using 20:1 in it but, todays oils are much better.
20 to 1 was for the oils they used to make. I run all my old saws, well my new ones too at 40 to 1. 50 to 1 will be just fine. The mix is about the quality of oil, not the age of the saw.
its there --I pasted it below
Model: Pro Mac 55
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MANUFACTURED BY: McCULLOCH MOTORS CORP.
LOS ANGELES, CALIFORNIA, U.S.A.
SERIES OR ASSEMBLY NUMBER: 600031
YEAR INTRODUCED: 1973
YEAR DISCONTINUED: 1977
ENGINE DISPLACEMENT: 3.5 cu. in. (57 cc)
NUMBER OF CYLINDERS: 1
CYLINDER BORE: 1.812 in. (46.02 mm)
PISTON STROKE: 1.375 in. (34.92 mm)
CYLINDER TYPE: Aluminum with chrome plated bore
INTAKE METHOD: Piston ported
MANUFACTURER ADVERTISED H.P.: not advertised
WEIGHT : 15.6 lbs. (7.1 kg) powerhead only
OPERATOR CONFIGURATION: One Man operation
HANDLEBAR SYSTEM: Rigid
CHAIN BRAKE: Yes
CLUTCH: Centrifugal
DRIVE TYPE: Direct
CONSTRUCTION: Die cast magnesium
MAGNETO TYPE: McCulloch flywheel breaker point system
CARBURETOR: Tillotson HS
Walbro SDC
MAJOR REPAIR KIT: RK-23HS for Tillotson
K10-SDC for Walbro
MINOR REPAIR KIT: DG-5HS/T for Tillotson
D10-SDC for Walbro
AIR FILTER SYSTEM: Flocked wire screen element
STARTER TYPE: McCulloch automatic rewind on left side
OIL PUMP: Automatic with manual override
OPERATING RPM:
IGNITION TIMING: 26 degrees before TDC
BREAKER POINT SETTING: 0.019 in. (0.48 mm)
FLYWHEEL/COIL AIR GAP: 0.010 to 0.012 in. (0.25 to 0.30 mm)
SPARK PLUG TYPE: AC CS45T
SPARK PLUG GAP: 0.025 in. (0.63 mm)
CRANKSHAFT MAIN BEARINGS: Ball and caged needle roller
FUEL TANK CAPACITY: 1.5 U.S. Pints (791 ml)
FUEL OIL RATIO: 20:1
RECOMMENDED FUEL OCTANE: Regular
MIX OIL SPECIFICATION: McCulloch two-cycle chain saw mix oil
CHAIN PITCH: 3/8 in.
CHAIN TYPE: McCulloch
BAR MOUNT PATTERN: 11 link
SHORTEST GUIDE BAR SUPPLIED: 16 in. (40 cm)
LONGEST GUIDE BAR SUPPLIED: 28 in. (71 cm)
COLOUR SCHEME: McCulloch Yellow enamel with Black
