Engine will not turn over when hot, as if starter is bad(not) or weak battery(not) once cooled 5 minutes or so will start

 

How was it determined the starter doesn't have a problem?

 

I replaced starter, no change, original starter was good, replaced battery, no change

 

So we are on the same page,

When we are attempting to start the engine , we are cranking it over.
When the engine starts running , we say it fires up or starts running.

When cranking the engine it turns over , but has not started yet.

Now, if you are attempting to start the engine and it cranks over, but will not fire up and start , that is what we need to know.
Does it crank over slowly or at normal cranking speed, and not start running OR does it just crank and not fire up ?
If that is what is happening, we need to remove any spark plug and see if it is wet or dry. If it is wet , then the engine could be flooded with gasoline or no spark is present to ignite the mixture in the cyls. If the plug is dry ,fuel is not getting into the combustion chamber. We need to know the answer to these questions before going further, can you do this?

 

I should have been more precise in my description, when engine is hot it will not crank, it turns over very slowly or not at all, after a few minutes it will turn over slowly at first then it flares to life & starts

 

Did anybody clean the battery cable connections where they connect to the engine?
Looking at them does nothing, they need to be removed , cleaned then reinstalled to eliminate any poor connection problems there.

Only way to verify battery cables are OK is to do a voltage drop check., which must be done when attempting to start the engine( Under load).
If corroded internally, could be causing a voltage drop when hot.

Did anyone mess with the ign timing?