How does altitude affect jetting?
Elevations also mess with jetting because of the dense air. Higher altitude (thinner air) requires less fuel or leaner jetting to run correctly.
How do you jet a high altitude?
The general rule for jetting is to drop one main jet size for every 2,000 feet of elevation increase. You can also go one clip position leaner on the needle jet. This is a good start for high-altitude adventuring, but depending on the temperature and humidity, you may need to go leaner or a touch richer.
What size main jet should I use?
A larger jet number means a bigger hole and more fuel. A smaller jet number has smaller holes and should be used if your engine needs to run more lean. Whether your machine is running too lean or too rich is a good starting point for choosing your jets, but using a jet calculator minimizes trial and error later.
What happens if my main jet is too big?
For example, using too large of a main jet will cause more fuel to enter the combustion chamber than it can efficiently burn. This will result in a “sputter” at full throttle. It could best be described as a rapid misfire.
Are there jets that do not conform to factory size?
Many jets are produced which do not conform to factory original. Jets may look correct but the orifice (hole) sizes are incorrect. Many places that sell jets are unaware of the differences hence the trouble encountered with buying jets from different dealers and the ‘used-jets’ bin at the dealer.
What kind of jet Kit do I need for a quad?
We still have to compensate for different elevations and temperatures. The odds of two quads being equipped the same, run at similar ambient temperatures and elevations is very low. The jet kit from company ‘X’ says to use jet 142 for aftermarket exhaust and air filter at elevations of 3000 feet.
When do you need to increase jet size?
As mentioned in step 1, you’ll need to increase the jet size for lower altitudes, while a smaller jet size will be needed for higher altitudes. Make the size change in increments of one to two sizes at a time.
Are there different sizes of jetsrus Jets?
All Jetsrus jets have been manufactured in the same plants since we opened. That means if you need a jet 1 size up or down that is what you will get from us. If you buy from a different store today, and need more jets in the future they may not be correctly sized. Many manufacturers have their own numbering system.
What kind of jet engine do I need for high elevations?
The parts catalog for your engine (available from your Honda dealer) lists two optional main jets for use at higher elevations. For elevations above 5,000 feet but below 10,000 feet (1,500 to 3,048 meters), use the first size smaller jet. For elevations above 10,000 fee t, the second smaller jet should be used.
What is the size of a Mikuni jet?
Main jet is mikuni type 4/042 size 200. Current conditions 1000 feet elevation at 70° deg; F. New condition will be 8000 feet and 60° F. What jet size is needed? 1. Start with the elevation change of 7000 feet (8000-1000=7000).
How big is a jet engine at sea level?
Consequently, the correct jet size is 0.60 mm (#60). The rest of the chart is just for approximating what percentage of sea-level horsepower will be produced by a correctly-jetted engine at higher elevations. At 7,200 feet, an engine will produce about 75% of its rated horsepower. Tip:
How big of a jet do I need for a Honda generator?
Example: The Honda EU2000i generator uses a 0.62 mm main jet (#62) as the standard size. The two options listed are a 0.60 mm (#60) and 0.58 mm (#58) jet. The owner wants to operate this generator at 7,200 feet for an extended period. On the elevation scale at the bottom of the chart, select 7,200 feet (between 7 and 8 on the scale).
How do I know if my main jet is too rich?
If the pilot circuit is rich, the engine will have a rough idle or may not return to idle without “blipping” the throttle. You may also notice a distinct smell of raw fuel and some eye irritation from the exhaust.
What is considered high altitude for carburetors?
FOR HIGH ELEVATIONS When the carburetor is modified for high elevation operation, the air-fuel mixture will be too lean for low elevation use. Operation at elevations below 2,000 feet (610 meters) with a modified carburetor may cause the engine to overheat, and result in serious engine damage.
Do you jet up or down for altitude?
Power goes down with higher altitude.” For small changes in altitude, carburetors will compensate without any modifications. For larger altitude changes, carburetor jetting adjustments may be needed. A rough estimate is one to two jet size reduction for every 1,000-foot elevation increase.
What happens if main jet is too big?
How much horsepower do you lose at altitude?
Generally speaking, an engine loses three percent of its rated power for every 1,000 feet of altitude gained. This means you could lose as much as 20% of your vehicle’s horsepower if you drive it from sea level to Big Bear Lake (with its 6,750 elevation).
What happens if main jet is too small?
Be careful: most engine jams occur when the main jet is too small. A lean fuel/air mixture will cause the engine to overheat fast.
What happens if main jet size is smaller?
Installing a smaller size jet will reduce fuel flow, which is ideal for high-altitude conditions where air is limited, where a larger jet size increases fuel flow for oxygen-rich, low altitudes.
What happens when carburetor is jetting for high elevation?
CARBURETOR JETTING FOR HIGH ELEVATIONS At high elevations, an engine’s performance will dec rease, and fuel consumption will increase due to the air being less dense. If a Honda engine will be used at an elevation above 2,000 feet (610 meters), its
How do you change jet size for higher altitudes?
As mentioned in step 1, you’ll need to increase the jet size for lower altitudes, while a smaller jet size will be needed for higher altitudes. Make the size change in increments of one to two sizes at a time. Screw the new jet size into the jet mounts within the metering block, with a screwdriver or pair of pliers.
When do you need a smaller jet in a carburetor?
When the operating altitude of the engine will be 2000 feet higher than your normal altitude, you’ll need to insert a jet one or two sizes smaller than the size currently installed in the carb, which reduces the amount of fuel entering the engine to match the reduced level of oxygen in the air.
When to adjust the pilot screw for altitude?
Altitude and temperature main jet correction factor C chart. If C is 0.95 or below, lower the jet needle one groove and screw the pilot screw out 1/2 turn. Jet needle position and pilot screw adjustments are not needed if C is over 0.95.