Just purchased riding mower with this engine, strong smell of fumes. Changed air filter, plug tried spray carb cleaner,  gas good ,any other suggestions ?

Just purchased so I have to ask, bought as is or is their a warranty?

Sounds like someone "dinked" with the carb and didn't reassemble correctly.
 
Post an engine model # so we can look up a parts diagram.  I suspect they left a main jet
out or seal...  
 
Comparing the diagram to your carb (disabled) and your carb should find your issue.
 
I assume you checked to make sure the choke is FULLY opening.
 
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