1975 johnson evinrude snowmobile service repair manual these are the alternate firing 399 35 HP 426 40HP 646 50HP JX and Skimmer sleds +++++++++++++++++++++++++++++++++++++ Length .................................. 103.2 inches Width .................................... 35.4 inches Height ......................... 43.4 inches with windshield 34.9 inches without windshield Engine. ............. OMC 2 - cycle Alternate Firing - 2 Cylinder Rating ......................... 399CC 35 HP at 6750 RPM 436CC 40 HP at 6750 RPM 646CC 50 HP at 6750 RPM Starter ................................. Manual rewind Variable speed drive ..... Centrifugal operated sheave engages V-belt Overall ratio ................................. 4.43 to 1 .......................... '7 Final drive Silent Drive Chain Sprocket ratio standard ..................... 135 - 17:39 145 - 19:39 165 - 19:39 Muffler .................... Tuned for maximum performance Brake ....................... Caliper - Flange on secondary Throttle. ............................... Thumb operated Track ............... Rubber - Polyester Cords fully adjustable Width ................................... 15.5 inches Skis ............... Formed steel equipped with leaf springs and replaceable wear runners. Seat ........... Vinyl coated cover, molded urethane foam cushion Hood ................................ Molded fiberglass Headlamp ....................S ealed beam Westinghouse 7700 Taillamp/Stoplamp. ............................. GE 11 5 7 Acc. ~peedometer/~achometelarm p ................. GE 1816 Fuel tank ........... Capacity - 5 Imperial gallons, 6 U.S. gallons Fuel .................. Gasoline - Premium or regular leaded Lubrication ...................... OMC brand 50:1 lubricant Carburetor ...... TillotsonHD diaphragm type with accelerator pump RPM Ratings Idle .....................................13 00 * 200 Transmission belt engaging speed .................................. .3300 * 300 Ignition Breakerless magneto C.D. (Capacitor Discharge) ignition Spark plug .......................... Champion UL-77V Advance sensor coil resistance. ............... 17 to 19 ohms Retard sensor coil resistance ................ 28 to 30 ohms Charge coil resistance (2 coils) total of .......... 600 & 50 ohms