Small Engines (Lawn Mowers, etc.): Craftsman Eager-1 Replacement Engine, craftsman eager 1, engine replacements

Question
What would the Tecumseh replacement engine part number for the Craftsman Eager-1 lawnmower 6.75HP, Model # 917377610, Craftsman engine part number 143.986706?  

Are there alternative Tecumseh engine replacements which have the same mounting and shaft that can also be used but have either 6.0HP or 6.5HP in the event the 6.75HP is not available?

Also any good place that the engine replacement would be available from?

Answer
Phil
Are you sure this is a good engine # 917377610 I can not find that in the data base we have and it is up to date.I think they do not make a replacement engine for this as I have the same push mower. Does this one have the electric start? I will look more into this.