Small Engines (Lawn Mowers, etc.): Honda Lawn Mower, honda hrb, valve lifter

Question
I have a Honda HRB-215 Lawn Mower with a GXV140 engine, about 8 yeras old. The engine stopped running and I disassembled and found the "Oil Defense Pipe" (plastic) loose and crushed inside the engine and a piece blocking open the intake valve lifter. I can not find out what the "Oil Defense Pipe" is for and since the local parts supplier did not have one in-stock, I reassembled the engine with new gaskets and oil seal. I checked the clearance on the Overhead Valve rocker arms and adjusted to about .005 in. I made sure the marks on the crankshaft gear and the camshaft gear were aligned. Now the problem. The engine is very difficult to start. I have verified gas is getting to the engine. I have verified that I am getting spark and I installed a new spark-plug. I do believe the problem is ignition. I finally got the engine to start and it runs smoothly. Once it cools down, it will not start again unless I pull and pull! How can I verify the ignition is good? Is it possible that the crankshaft/camshaft gear alignment is not correct? What about valve rocker arm adjustment? I would appreciate any tips and help. I am trying to avoid taking to a repair shop.

Answer
I have had mis-adjusted valves cause the same porblem, but .005 sounds good.  You may want to check the clearance again to make sure they are still .005

As for testing ignition, Honda sometimes uses CDI which is both easy and difficult to trouble-shoot. What?  Usually, if the ignition system fails, no spark will be produced at all.  Once in a while, very rare, some is the CDI modules will just work poorly.  These are very difficult to trouble-shoot, mostly you just have to replace the module.  I had one that passed all the manual checks, started and ran fine once re-assembled but refused to start the next morning.  It did this twice before I finally replaced the module.

I would check the flywheel key and cam timing.  This could cause your problem.  Check the flywheel key first, since that is the easy one to check.  It's possible, but not likely the cam is off a tooth or two.

Has the carburetor ever been serviced?
Eric