I recently bought an Alroh 54D cylinder mower that came with a Tecumseh engine that doesn’t start. Seller indicated likely issue with the carburetor. He poured some oil into the combustion chamber
through the spark plug opening and engine can then be started up successfully.

I tried to search for some information on the engine as reference to service/clean the carburetor but failed to find information related to this engine. Posting this thread to get some help in identification of this engine and in getting related information to attempt a service.

Photos show the mower, engine and carburetor. Any advice is appreciated. Thank you

That has a pretty basic carb on it.
 
Looking at the outside, it's likely pretty varnished up inside.
 
Remove the carb, then the float bowl.  Remove the float and needle and clean those as well
as the opening to the bowl.
 
I don't remember how the main jet is situated but it will be right down the middle 
where the bowl bolts to.  If you see a slotted jet down in the hole, try carefully to remove it 
for a good cleaning.
 
This is a carb after cleaning to give you an idea what's inside:

 
 
.

This is the same carb B4 cleaning. 
The main jet IS the bolt holding the bowl on. 
They'll be a hole sides thru the jet AND  a smaller hole 
from the top down. That MUST be clean.