Basically, problem with engine goes idle was solved after we cleaned carburetor. But engine still starts very bad. We found that the problem is he gets too much fuel. There is a main hose from a regulator to the carburetor. When we are taking this hose off during the engine starts we are reducing the amount of fuel and the engine starts properly. So my question is how can I reduce fuel flow. This AISAN type C regulator seems doesn't have a manual regulation. The lock-off valve seems works fine.