Whe I clean a BADLY dirt filled engine...

I remove the carb and backplate... flush some fuel into the case and let it drain out where the carb was. (collect the fuel in a whipped topping or butter tub) Then I wash the carb out in the wasted fuel.

Then I decide if I need to dissasemble the engine or carb more to get more dirt out. All parts that are dissasembled are swished around in the waste fuel... then dried with a terry-cloth rag and placed on a paper towel or newspaper IN THE ORDER THEY WERE REMOVED.

When all parts are clean... assemble in opposite order of removal. Be careful not to over-torque the backplate screws. Even the metal backplates can be broken. (or the case threads stripped)