1944 Gray Marine BB Updraft Carburetor – Carburetor number 586S. Correct for 4 cylinder engine, model 4-52.
3 7/16″ bore, 4 3/8″ stroke.
Carburetor kit for this BB updraft carburetor
Sizes:
Flange size, 1 1/2″, 2 11/16 mounting bolt OC.
Throttle bore, 1 1/2″
Main venturi, 15/16″ I.D.
Air bleed through venturi, to idle passage .0669″ diameter drill.
Float Setting Top of float 1/32 – 1/16″ below top of surface of lower body
Balance Vent Tube Inside diameter, 7/32″
Gasoline Intake Needle Triangular, horizontal.
No 44 (.086″) drill in needle seat
Idle Jet Tube Jet size, .0236″ (60mm) drill
Idle Ports Lower port size .062″ to 064″ diameter. Top of port located .005″ to .009″ below lower edge of valve. Upper port size .053″ to .057″ diameter (for idle adjustment screw)
Set Idle Adjustment Screw 1/4 to 1 turn open. For richer mixture, turn screw out. Do not idle engine below 300 rpm or 6 mph
Vacuum Spark Port No. 69 (.029″) diameter
Main Metering Screw Adjustable 1-2 turns
Nozzle No 33 (.113″) drill, I.D.
Accelerator Jets 2 No 62 (.038″) drill 1/16″ from shoulder 2 No 62 (.038″) drill 3/8″ from shoulder 2 No 62 (.038″) drill 23/32″ from shoulder 2 No 62 (.038″) drill 1 1/16″ from shoulder
Air Bleed to Nozzle Vent tube size .048″ drill
Step Up Jet Power orifice size .0315″ (80mm) drill
Accelerating Pump Type, low pressure, delayed action.
Stroke Summer setting, inner hole, short stroke 9/16″. Winter setting, outer hole, long stroke, 1″.
Pump intake ball check size 1/8″.
Pump discharge retainer (in pump valve age assembly) No 52 (.0635″) diameter drill size.
Choke Manual butterfly type, with pressure relief poppet valve. Lever on left side.