I looked on the Walbro site and there isn't any WR series,but is a Wt series and a Wt-38 which has a 9.53 mm venture. On the Zama site the C1Q-P8 has a 6.5mm venture. Both are available on Ebay.
If this was a weedeater conversion I'd say try for a Walbro carb with an 11.11 venture,but don't know anything your engine, so I couldn't recommend one for your engine.
Last edited by Tidnab; 11-21-2015 at 04:58 PM.