How does a needle valve work in a carburetor?
When fuel is drawn up the main jet, the fuel level in the chamber drops, thus the float also drops. This opens the needle valve allowing more fuel to enter the chamber. When the float again rises with the fuel level, the needle valve will close off the fuel supply.
Is it better to run rich or lean?
Running lean can give you more power but to lean will blow your engine. Running too rich can also hurt your motor. Think of it when you are mixing gas for your weed wacker. It is always safe to add a little more oil than not enough to the mixture.
What is a rich air/fuel mixture?
If exactly enough air is provided to completely burn all of the fuel, the ratio is known as the stoichiometric mixture, often abbreviated to stoich. Ratios lower than stoichiometric are considered “rich.” Rich mixtures are less efficient, but may produce more power and burn cooler.
Does running rich damage engine?
Running rich is not good for the engine as it builds up carbon deposits on valves and pistons that destroy the engines performance. If it’s slight, then exhaust will be “dirtier”, power will be down, the plugs, exhaust, and piston crowns will tend to get sooty over time.
What happens if an engine runs too lean?
An engine that is running lean is not good. Beyond a drop in performance, you can experience damage to the spark plugs, pistons, valves or catalytic converter. The fuel itself acts as a coolant as it enters the cylinder. Reduce the cooling effect, and temperatures inside the engine get too hot.
What does running lean or rich mean?
A vehicle’s fuel mixture refers to the ratio of fuel and air in the combustion process. When you have too much fuel and not enough air, your car is considered to be running “rich”. When you have too much air and not enough fuel, your vehicle is considered to be running “lean”.
Can bad spark plugs cause engine to run lean?
Yes. If the fuel is not burning optimally, some raw fuel will be expelled through the exhaust. The function of an 02 sensor is to detect how rich or lean the engine is running based on the amount of oxygen in the exhaust. when it does, it pulls fuel from that bank of cylinders.
How do you read a lean or rich spark plug?
Spark Plug Indicators By Fuel The longer the period of use, the darker the color. A rich mixture results in a dark porcelain coloration from carbon buildup. The darker the color, the richer the mixture is. A lean mixture can be indicated by excessive heat indicators on the plug and ground strap.
What should my AFR be at idle?
Most stock to slightly modified engines will run just fine at an AFR of 15 and yield better MPG. If you prefer better PERFORMANCE then we suggest to run an AFR of 14 or even richer to around 13.
What is a rich AFR number?
Lean or Rich Mixtures When an air/fuel mixture has too much fuel, it is rich. An AFR higher than stoich = lean. An AFR lower than stoich = rich. A lambda value higher than 1 = lean. A Lambda value lower than 1 = rich.
What does a bad air fuel ratio sensor do?
If an air-fuel ratio sensor has become “lazy,” over time it will send a delayed signal to the computer, which will result in an overall delayed response for the entire engine. The vehicle may experience a sluggish or delayed response when accelerating, as well as a noticeable loss in power and acceleration speed.