Tecumseh 12HP help Adjust Valves


Old 11-07-12, 02:53 PM
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Tecumseh 12HP help Adjust Valves

Please help....Have an old 12hp Tecumseh 143.386012 on Craftsman mower. Began to get hard to start each time now it won't start anymore....Staring reading some of these posts and began to mess with the valves. What is gap on intake and exhaust valves? Have gas and spark. Which nuts are the ajusting nut and the set nut? Could carbon buildup be the problem. I trying not yo take the head off.
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Old 11-07-12, 10:32 PM
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Turn the engine to top dead center on the compression stroke, then set both gaps to .005". The outer nut is the lock nut, the other is the adjustment nut. Once you get the clearance set, hold the adjuster nut still and tighten the lock nut.

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