An engine runs by the combustion of a mixture of oxygen and gasoline. If this mix has too much oxygen, it is said to run lean. When the mixture has too much gasoline in relation to oxygen, it is running rich.
Too rich and you will get black smoke from exhaust. You can also read the spark plugs. way too rich and the engine will bog down or flood out in extreme situations. If it's running too lean, the rpms will get erratic.
it sense oxygen come out from your engine to tell the PCM your car is running rich or Lean
14.7:1 --- Air : Fuel Ratio. perfect. not lean, not rich.
Engine is running rich
Dry is good, but white is bad! It means that the engine is running lean, which will result in the engine running too hot and can cause serious engine damage (even seizure). Below is a guide to reading the spark plug color. Black = Rich. The fuel/air mixture is too rich (too much fuel, not enough air). Tan/Brown = Normal. The fuel/air mixture is correct. White = Lean. The fuel/air mixture is too lean (too much air, not enough fuel).
this could be a number of reasons it could be your mixture screw or it could be running lean or rich the best thing to is a plug chop see what colour it is if its black and oily its running rich if its white its runing lean also if its running lean your engine will sound flat and could course it to seize or the main jet could be to big or to small its always best to over jet a a 2stroke and work down till you feel the engine getting better hence the bog going away hope this helps
Running lean basically means that your Air Fuel Ratio is off and there is more air than fuel, which creates a lean condition. It is called the "Stoichiometric" value. The correct ratio is 14.7 parts air to one part fuel. If you are running for instance a ratio of 16 to 1 then that is lean. Basically too much air when compared to optimal air fuel mix. A ratio of 12 to 1 is too rich. The problem with a lean condition is that the engine will run hot. Normal logic would suggest that with less fuel there would be less heat generated, but it is not the case. A lean condition will actually make the engine run hotter.
running lean can cause your 400ex to backfire ..if it backfires on deceleration its lean ...if it pops on acceleration its running rich.====carb issues
"Rich" and "lean" refer to the air/fuel mixture. Rich means a higher proportion of fuel than is needed and lean means less. An overly rich mixture can foul plugs, cause sluggish performance and promote carbon buildup in the combustion chambers, as well as decrease fuel economy. An overly lean mixture can cause jerky, hesitant performance, overheating and in extreme cases even melt a piston crown.
Code 173 indicates the oxygen sensor is telling the computer that the engine is running rich.
That is an oxygen sensor, it tells the computer how rich or lean the engine is running on bank 1. The computer uses this info to control how much fuel the engine gets.
If a car is running too rich, the air to fuel mixture is not right. Running rich means that there is too much fuel (gas) going into the engine for the amount of air going in. On the opposite side, too lean would mean that there is not enough fuel going in for the amount of air. Cars can run rich when the oxygen sensors go bad, or on older cars, if the carburetor is not adjusted properly. Running rich can be accompanied by a distinct exhaust smell, and in the extreme cases, some blue smoke. The inside of the exhaust pipe will be black if a car has run rich for any amount of time (when it's cool, take a light colored rag and wipe it inside the end of the tailpipe-if it comes out black, the car is probably running rich).