Small Engines (Lawn Mowers, etc.): new leaf blower where are the mixture screws?, yard man leaf blower, walbro carb

Question
New Yard man leaf blower runs rich at wot. Will start to run right as it runs out of fuel. It has a walbro carb. The top of the carb has a black like screw top with two flat sides close to the engine case. The place next to it is a hole that is not threaded and is solid across the bottem. Is the black the high speed? The manual says carb adjustment to be done by dealer but I want to use it not wait on it. Thanks

Answer
It's hard to say for sure as Walbro has hundreds of variations on their carbs.  However, try adjusting the screw that you think is the high speed.  If it makes no difference at high speed, return it to its original setting.  Usually there are two mixture screws side by side with the one closest to the engine being the low speed mixture and the other the high.  Make sure if you do adjust the high speed, lean it out until the engine is at max RPM, then open it 1/8 of a turn to provide more fuel under load.  Hope this helps.