helping a friend with almost new craftsman rear tine tiller that sat for 2 yrs with ethanol fuel in it.   fuel turned to a  very thick tar/varnish consistency and wasfrom tank to combustion chamber.  i down to combustion chamber cleaning need a best practice suggestion forethod and appropriate cleaner    thanks

Carb or brake cleaner will work fine. 
 
Carb cleaner is a bit stronger.
 
A toothbrush will also hasten cleaning the accessible, really tough spots..

Quote:
 
" i down to combustion chamber cleaning".  Are you referring to the combustion chamber itself?
 
If so, get the piston TDC (compression stroke if a 4 stroke), and let it soak with Sea Foam for a couple of days..