Your compression figures look ok to me (I don't know what compression ratio you're running, but if you multiply 14.5 by your CR you'll get the max. theoretical cylinder compression pressure, then deduct maybe 5% for induction/compression losses, this should give you a fairly accurate figure to look for e.g. 14.5x9 = 130, minus 5% = 124 psi, the original 500 as standard (stock) had a CR less than 9:1).
Are you getting a good spark at both spark plugs when hot, sometimes ignition systems can 'act up' when hot e.g. faulty condenser or coil.
To check - disconnect both plug leads at the spark plugs, insert spare plugs into the ends of the leads, earth the plug bodies against the engine metal and have someone spin the engine over with the ignition on - you should have a good spark at both plugs.
Hot starting problems are usually fuel related e.g. engine flooding or fuel vaporisation.
Starting Technique?
When starting a hot engine, don't pump the accelerator pedal -if the carb has an accelerator pump fitted, doing so can flood the engine.
Try just opening the throttle slightly i.e. partially depress and hold the acc. pedal steady while turning over the engine.
If you think the engine is flooded, press the acc. pedal to the floor and hold it there while turning the engine over.
If the engine has flooded, the spark plugs will be wet with fuel, but they will also be wet with fuel if there is no spark, so rule out faulty ignition first.(which is why I suggested testing the ign. system first). You might also be able to smell petrol in the engine bay.
The usual cause of engine flooding, apart from incorrect technique, is either a leaking float valve, incorrect float level or occasionally a perforated float - but these causes will usually result in poor running at other times. Is there any sign of fuel in the drain tray fitted at the base of the carb - there will be if the carb is flooding. A carb. strip and inspect will be needed to rectify these faults.
***a leaking float valve or incorrect float level are the 2 most common causes of difficult starting when hot***
Difficult hot starting can also be caused by lack of fuel - usually as a result of heat soak into the fuel lines resulting in vaporisation.
Spraying some carb or brake cleaner or Eazi-Start into the carb intake can be used to rule out lack of fuel as a cause. To avoid vaporisation, try leaving the engine lid up (open) (to reduce heat soak) when you stop with a hot engine, then see if it starts better a little later, while still hot. If this helps, you could try fixing some insulation over the fuel lines, but bear in mind that this is not necessary on standard engines even in hot countries. Sometimes a weak fuel pump can contribute to poor hot starting by being slow to prime the fuel line if vaporisation has occurred, but more usually shows up if the car is driven at high revs for a while (pump cannot keep up with fuel demand of the engine).
There's other possible causes for poor hot starting but the above are the most common. Have you checked your valve clearances (valve lash)[?B]. The valves on the 500 have a tendency to close up, they're checked/adjusted cold. You don't say if you checked your compression figures with the engine hot or cold but if you checked them cold, maybe repeat the tests with the engine hot or check the valve clearances, just to rule this out. This is important, so I'd recommend doing this and the test for sparks first before going near the fuel system.
P.S. Don't start changing parts until you've determined what exactly is faulty, might only be some adjustment is needed.
Hth, if not, report back with your findings and we can take it from there.
Al.
