There are solenoids for air on the carb. My problem was: Problem: high fuel consumption, worked only up to half throttle, with WOT black unburned fuel was coming out of the exhaust and RPM went down. Removed the intake airfilter, without airfilter it ran good = more air. So I bought a new airfilter, installed it, same trouble. Check spark plugs (yes all three of them, hehe), ignition wires, distributor and rotor, fuel pressure regulator, all fine, spark plugs were black from unburnt fuel. Then I asked a friend who knows these engines very well and he showed me the repair of the carb as shown here http://blogs.yahoo.co.jp/kurumanosentakuya/51811442.html Actually we did not have to disassemble the complete carb, but he told me to order 2 parts which are usually the problem. attached to the carburetor 16024-PZ3-000 solenoid for air 16031-PZ3-000 solenoid for air 16024 solenoid was dead and did not move, now full power again. Cost for both solenoid valves with accessories, even washers, new bolts etc, all in the package, $50 here in Japan. My engine is a Honda E07A SOHC 12 Valve Displacement: 656cc
