What are the running symptoms of the leak? I'm no expert but have dealt with leaks causing two different problems- one, lower compression and two, fuel draw or idling problem. And like your engine, I've heard the leak but had to couple it with the running symptom to find the root problem. Lately, I'm amazed at how badly the seals are on the needle valves of these chinese engines. Brand new out of the box and I've got to put fuel line or different orings on the needle valves to get them to run and idle right.