1970-1979 Ski-Doo Snowmobiles Service Manual, Page 26Get this manual
PERIODIC MAINTENANCE AND TUNE-UP tune-up impossible as well as affect performanceA small air leak can also cause serious damage by allowing the engine to run on "too-lean" fuel mixtureTune-up Hints
19 4When using feeler gauge to set breaker points, ensure that the blade is wiped clean before inserting between the points5Ensure that points are fully open when setting gap with feeler gauge6Be sure that feeler gauge is not tilted or twisted when it is inserted between the contactsClosely observe the points and withdraw the feeler gauge slowly and carefullyA slight resistance should be felt, however, the movable contact point must not "spring back" even slightly when the feeler gauge blade is removed7If breaker points are only slightly pitted, they can be "dressed down" lightly with small ignition point fileDo not use sandpaper as it leaves residue on the points8After points have been installed, always ensure that they are properly aligned, or premature pitting and burning will result (Figure 21)Bend only the fixed half of the points; not the movable arm