Small Engines (Lawn Mowers, etc.): tecumseh OHV17 small engine, murray riding mower, wooden dowel

Question
Ben,  How do you adjust valves ...into what spec...for a OHV17 Tecumseh engine on a Murray riding mower?

Answer
Tom

Since all i have to go by is just a model # and no other numbers here is  a close answer.

You need to watch valve movement to ensure you are on the power stroke. The power stroke immediately follows the compression stroke and is immediately before the exhaust stroke. Since you have an OHV engine, it is much easier to watch than it is on a flat head engine. With the rocker cover off (as I'm sure you're already there) rotate the crankshaft clockwise (as viewed from the flywheel end) and, yes, use a long wooden dowel in the spark plug hole to determine piston position and watch for the intake valve to open. On the next stroke (which will be an upstroke), you will take the piston to top dead center (TDC) and then continue in the same rotational direction 1/4 inch (of your dowel movement) past TDC. You are now at the position to set both valve clearances. Yes, this engine does have a MCR and therefore is important to follow my directions. Yes, .004" is correct for both valves. In order to determine if your MCR is functional, you must first set the clearances and then again rotate the engine CW and watch the valve closest to the PTO (power take off) end of the crankshaft for movement at just before TDC on the compression stroke. Mind you, it will be brief in duration and minimal in lift. Hope this helps