Welcome to the DoItYourself Forums!

To post questions, help other DIYers and reduce advertising (like the one on your left), join our DIY community. It's free!

Tecumseh 12HP help Adjust Valves

risingson's Avatar

Join Date: Apr 2007
Posts: 37

11-07-12, 02:53 PM   #1  
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.

Sponsored Links
cheese's Avatar
Forum Topic Moderator

Join Date: Jul 2001
Posts: 16,565

11-07-12, 10:32 PM   #2  
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.

"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

Search this Thread