Small Engines (Lawn Mowers, etc.): Briggs wont start. No compression?, internal passages, fuel mixture

Question
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Followup To
Question -
I have a 5hp Briggs model 130232 that won't start.  It occasionally sputters , but nothing more.  I've cleaned the carb and have clean fuel and good spark.  It seems to me that the compression is very low.  I've read that the "Easy Spin" Briggs motors turn very easily, but should "bounce back" if you spin the flywheel in the opposite direction.  I get no indication of compression in any direction.  I put my finger over the spark plug hole and nothing.  When I had the carb off I plug the intake with my palm and spun the flywheel and noticed good suction!?  I should also say that the head gasket has been replaced and I removed and cleaned (wire wheel) the carbon from the valves as well.  Any ideas
Answer -
If the compression is leaking past the valves, listen for a whisping sound through the exhaust.  This will indicate compression loss.  I suspect, if this engine wasn't consuming excessive amounts of oil, it will require the valves to be lapped and the tappet clearances set (~0.006" INT, ~0.010" EXH).  Hope this helps.

Thanks for your reply.  Before I played with the valves again I thought I'd try something I do with my hotrods.  I put about a tablespoon of oil in the cylinder to check if the leak was in the rings or valves.  When I pulled the rope I got all kinds of compression!  Just for grins I put the plug back in and pulled the rope after 3 pulls it started and ran for 2 hours until I shut it off!  Only problems 1) It only runs at idle or slightly above, if you pull the governer it'll shoot right up! 2) Fuel mixture screw has absolutely no effect (all the way in or 4 turns out no difference).  I figure rebuilding the carb (again) and adjusting the governer?  Any ideas?

Answer
You are correct, if the fuel mixture screw has no effect, the carb has a blockage.  Make sure you use a piece of tag wire to push through all of the internal passages.  If this is just an air vane governor, the only adjustment is replacing the governor spring.  Hope this helps.