# How can i find TDC on Tecumseh 12hp ovxl120?



## jcundiff (May 17, 2008)

Push rod slipped off rocker arm, need to put back on and reset valve lash etc. New to small engines, not sure if I need to find TDC first then reassemble ?? if so how do I find TDC, on cars its marked on the flywheel...not sure how to find tdc on this ohv 12 hp tecumseh motor. solid state ignition. can anyone help???? tractor is 1988 model.


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## phillipmc (Jan 27, 2008)

Pull the blower housing off to access the flywheel On the flyhweel is a magnent. Then look for the coil pack which sits almost touching the flyhweel where the spark plug wire comes from when the magnent is under the coil pack you are close pull the spark plug out and get a flash light shine in the spark plug hole you should see the piston when the piston stops its upstroke and just before starting its down stroke should be TDC. When you are adjusting your valve clearance make sure you adjust it to factory specs. Someone on here with access to manuals should know what that is.


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## 30yearTech (Sep 14, 2006)

You don't have to take the blower housing off or access the flywheel to find the TDC of your engine. Go ahead and reassemble the valves and remove the spark plug, rotate the engine over slowly while observing the valve operation, after the intake valve closes slip a screw driver or other probe into the spark plug hole and continue rotating the crankshaft. The probe will be pushed upward as the piston approaches TDC. When the probe starts to slightly drop back down, stop this is the position for adjusting the valves.

Everyone on this forum has access to the service manuals for many of the engines discussed on here. The links are in the sticky post of the 4 cycle engine thread. In case you can't find it, for your engine the setting is .004" for both intake and exhaust.

Best of Luck...


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## jcundiff (May 17, 2008)

Thanks a bunch for the info!


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