Small Engines (Lawn Mowers, etc.): Hard starting 5BSXS, mtd yard machine, valve service

Question
Eric,

These are the model #'s from my B&S MTD Yard Machine.  It is a 17.5 hp with a OHC.
276016
5BSXS
50112 VP

The engine does not want to turn over well when starting and the problem is getting progressively worse.

It has a new battery with a good charge.

The air cleaner and intake are clean.

I can pull the spark plug and the engine will turn over well with the starter.  After doing this I can put the spark plug back in and it will normally turn over well and start.  Seems like it just depends on where in the stroke it stops.

I read this may be a problem with the valves being out of adjustment.  If this is the problem how do I adjust the valves?  Do you have instructions and clearances.

Thanks, Paul

Answer
Valve information:

http://faqs.custhelp.com/cgi-bin/faqs.cfg/php/enduser/std_adp.php?p_faqid=1439&p...

Valve service link:

http://faqs.custhelp.com/cgi-bin/faqs.cfg/php/enduser/std_adp.php?p_faqid=3441&p...

Have you dis-conneceted the battery and cleaned the battery terminal posts and cable ends with a wirebrush?  I have fixed a lot of hard starting problems just my cleaning the connections.

Let me know if the links help.
Eric