Universal Carburetor Adapters:

These adapters enable a short pipe nipple to be attached to a small engine’s carburetor using the air cleaner bolts or studs.  Check your application before ordering.

They are available for:

• 3/4 inch NPT. Generally used on 8-10hp engines like the Tecumseh HM80 ($5 flange only, $20 welded as shown)
• 1 inch NPT. Generally used on 10-13hp engines ($5 flange only, $25 welded as shown)

Chinese Honda clone 389cc 13hp carburetor adapter:

 

This is an exact fit application.  I scanned the air cleaner gasket, extracted the edges, and burned an exact duplicate without vent holes in .120″ thick steel.  It has a 1″ pipe nipple extension.

$5 flange only, $25 welded as shown

Yamaha 357cc 12hp carburetor adapter:

This is an exact fit adapter that fits a 2007 Coleman Powermate and possibly other generators.  The pipe nipple is 1 inch pipe.

$5 flange only, $25 welded as shown