Baffled by hard starting rider

[DKAudio]

I got a used Simplicity Coronet with a Kohler Command 12.5HP engine (CV12.5). I have gone through this thing completely and it still is hard starting. Last time I started it I put the choke all the way on like normal and it didn't even really sound like it was firing, I then moved the choke off a little and it popped/fired with smoke coming out the exhaust. Moving the choke back and forth I finally got it started. Once it is started it runs like a champ, I can put it on low idle if I get off of it and it idles super low, quiet and nice, no problems otherwise. This is what I have done...

Carb kit, cleaned thoroughly
New air filter
New fuel filter
New fuel lines
New oil and filter
Verified gas cap venting
New fuel pump
New spark plug
New flywheel key
Adjusted choke/throttle cable per the manual, with the choke on the choke plat is completely closed then as you back off the choke the throttle opens as it should.
Lubed and oiled all points per the manual
Measured coil resistance - good
Verified about business card thickness coil is from magnets on flywheel

What is left???

[mrcaptainbob]

Check the compression. Keep the throttle wide open and crank until the needle won't move anymore. Then put maybe a teaspoon of oil in the plug hole and crank until the needle won't move. The difference should be negligible. If it's too much difference, then the rings could be worn. By the way, did you check the valve clearance?

[DKAudio]

Check the compression. Keep the throttle wide open and crank until the needle won't move anymore. Then put maybe a teaspoon of oil in the plug hole and crank until the needle won't move. The difference should be negligible. If it's too much difference, then the rings could be worn. By the way, did you check the valve clearance?

Thanks, I don't have a compression gauge unfortunately, I'll see if I can borrow one from someone.

No, I have not checked the valves, that is something I have never done before.

[mrcaptainbob]

You can rent one from Auto Zone or O'Reilly's... As for setting those valves, there are manuals. A good forum for this is My Tractor Forum. I believe you can access their manuals as a visitor as well as a member...
try this:
Simplicity/Allis Chalmers Manuals and Literature - MyTractorForum.com - The Friendliest Tractor Forum and Best Place for Tractor Information

Yours may be in there....if not, join this forum and post your issue in the Small Engine Repair section:
Small Engines and Repair - MyTractorForum.com - The Friendliest Tractor Forum and Best Place for Tractor Information

[mrcaptainbob]

Any results?

[HayZee518]

I have a 13.5 hp briggs. My engine uses an extra lobe on the camshaft that opens the exhaust valve ever so slightly just to relieve the back pressure when starting.
Yours might have this.
About the valves - ADJUST THEM in the center is a torx screw loosen this up then make the adjustment with the larger nut and feeler gauges. then tighten the torx screw. this locks the valve rocker.