Unit 2 Engine Tech
List the 3 types of governor discussed in the chapter
1. Air Vane 2. Centrifugal 3. Vacuum
The 3 basic carburetor adjustments in the order in which they are performed
1. High Speed Adjustment 2. Idle Mixture Adjustment 3. Idle Speed Stop Screw
What are 3 basic functions that governor are designed to serve
1. Maintain Speed 2. Prevent Over-Speeding 3. Limit High and Low Speeds
For average applications such as normal yard lawn mowing, the air cleaner should be cleaned every ______ hours per season
25
Never soak carburetor parts in solvent for more than ______ minutes
30
A carburetor overhaul generally consists of doing what
Dissembling, Cleaning, and Replacing Parts
The ______________ carburetor can provide larger volumes of fuel for high speed power requirements
Downdraft
When an engine is designed for use in greater than normal dusty/dirty conditions, a ________________ air filter is installed
Dual-Element
A float that is set low will cause the engine to run lean or rich
Lean
The diaphragm in a carburetor forces fuel through the _______ _______ ______
Main Discharge Nozzle
Because there are many different designs, you should always follow the ____________ _________ when assembling a carburetor
Manufacturers Manual
The proper way to clean an air filter cartridge of the pleated paper type is what
Shaking it with the external side down
What should be done to dry type air filter elements when they become dry
Should be discarded and replaced with a new filter
The ability of a governor to maintain a preset speed without fluctuating is called
Stability
The main purpose of the engine primer is to produce a rich mixture for
Starting
The tips of the idle mixture and high speed needles should be
Straight and Smooth
A type of carburetor that is placed low on the engine, and has the air flowing upward into the manifold
Updraft
Air velocity must be higher in the __________ carburetor
Updraft
Which type of carburetor would normally require a smaller air passage than the other 2 types
Updraft
In a diaphragm type carburetor on a 2-cycle engines, the fuel is drawn into the crankcase during the upstroke or down stroke of the piston
Upstroke
Gasoline must be ______________ by the carburetor
Vaporized
The 2 types of governors used on small gas engines are what
1. Air-Vane 2. Centrifugal Flyweights
If an engine is equipped with a fuel pump and fuel is not being delivered to the carburetor, what things should you check
1. Fuel in the tank 2. Fittings connecting fuel line to tank and pump are tight 3. Pump filter clean and gasket on bowl is in good conditions 4. Pump is working
What are each of the 2 needle valve adjustments found on most carburetors called
1. High Speed Adjustment 2. Idle Mixture Adjustment
What are the steps involved in adjusting the idle mixture needle
1. Move throttle to the slow running position 2. Turn idle adjusting screw until idle is smooth 3. Adjust idle speed stop screw
Needle valve points in the carburetor float chamber are usually made from one of two materials. The two materials are what
1. Neoprene 2.Brass
What are the three types of air cleaners that are widely used in small gasoline engines
1. Oil Wetted 2. Dry Types 3. Duel Elements
How should one adjust the high speed carburetor needle
1. Open throttle wide 2. Turn needle forward 3. Turn needle backward until max speed is reached 4. Turn needle counterclockwise slightly
When the air filter becomes dirty, the engine will do what
1. Use more fuel 2. Lose power 3. Accumulate Carbon
The usual normal air-fuel mixture is a ratio of ____ part(s) of air to 1 part of fuel
15
Normal air-fuel mixture by weight is what ratio
15 to 1
An __________ ___________ is any area completely free of air or atmospheric pressure
Absolute Vacuum
A reservoir of fuel, located inside the nozzle, for use during rapid acceleration
Acceleration Well
The ______________ stores fuel for use during rapid acceleration
Acceleration Well
A device that is used to clean incoming air
Air Cleaner
If the gasoline supply and fuel pump operation are satisfactory but an engine still idles and accelerates poorly, where would you check for the cause of the trouble
At the carburetor-may be poor adjustments or defects
A soon as the intake valve opens or the intake port is uncovered in a gas engine, ___________ forces air through the carburetor and manifold to fill that vacuum
Atmospheric Pressure
The weight of air at sea level
Atmospheric Pressure
This is a device for automatically mixing fuel in proper proportions with air to produce a combustible gas
Carburetor
This contains all of the parts needed for a typical carburetor overhaul
Carburetor Kit
The plunger-type bulb, when pressed, forces fuel through the ____________ ____________ and into the carburetor throat
Carburetor Nozzle
What type of governor utilizes pivoting flyweights
Centrifugal(mechanical)
To expose carburetor passages, Welch plugs should be removed with a small, sharp
Chisel
A valve that is placed in a carburetor air inlet to restrict the volume of air admitted
Choke
The carburetor ____________ is a round disc mounted on a shaft located at the intake end of the carburetor
Choke
Many choke and throttle plates have _________ __________ on them so that they can be installed in the proper position
Coded Markings
After all parts are clean and dry, they should be inspected for what
Damage and Wear
The safest solution in which to wash an air cleaner plastic foam element is what
Detergent and Water
A flexible partition or wall separating 2 cavities
Diaphragm
This is a type if carburetor that does not have a float
Diaphragm-Type Carburetor
Designed to retard fuel flow to the engine at part throttle
Economizer Circuit
If the throttle and/or choke shafts are loose(worn holes or shafts), the engine will run
Erratic and Lean
How often should an engine air cleaner be examined
Every time the engine is serviced or repaired
Paper toweling is used to dry carburetor parts. True or False
False-This may leave lint behind....Use compressed air
A small, sealed vessel made of brass or plastic
Float
When the primer bulb is pressed, it forces air into the __________________ on float-type carburetors
Float Bowl
This is a type of carburetor that uses a small vessel made of brass or plastic, for controlling the flow of fuel
Float-Type Carburetor
The air vane governor is operated by the stream of air created by the __________ cooling fins
Flywheel
This is used to push fuel non-gravity fed fuel systems
Fuel Pump
A carburetors primary function is to mix proper proportions of ________ ____ ________ to operate the engine
Fuel and Air
A type of throttle control that uses a mechanical, hydraulic, or electrical device that controls and regulates speed
Governor
This is a device that controls and regulates engine speed
Governor
This is a type of fuel system that does not use a fuel pump
Gravity-Fed System
When adjusting this screw on the carburetor, open the throttle wide open, the adjust this screw
High Speed Adjustment
This is a term describing an engine that is increasing and decreasing in engine speed
Hunting
In diaphragm carburetor operation, during intermediate speeds, fuel flows from the ________ __________
Idle Discharge
This is a third screw adjustment that is often found on carburetors
Idle Speed Stop Screw
The acceleration well fills when the engine is
Idling
If an engine has a sediment bowl on the fuel strainer and water is present in the fuel, the water will be visible where
In the bottom of the bowl
The primary purpose of air bleeds is to
Increase the air-fuel ration
When servicing a diaphragm carburetor, the diaphragm should be checked for defects that can cause what
Leakage
Since blade tip speed is a function of blade length and engine rpm, longer blades require _________ engine speed
Lower
A type of carburetor that has the air slowing horizontally into the manifold
Natural Draft
The choke valve in the carburetor is always located where
Nearest the intake end of the carburetor
When disassembling a carburetor, all _____________ parts should be removed
Nonmetallic
________________ carburetor parts should never be placed in cleaning solvents
Nonmetallic
Air or centrifugal force is used to _________ spring pressure in small engine governors
Oppose
This generally consists of disassembling, cleaning, and replacing parts on a carburetor
Overhaul
It is important to inspect hollow, brass-type floats for what
Pinholes and Dents
A hand operated plunger,which, when depressed, forces additional fuel through the main nozzle prior to starting a cold engine
Primer
This is a manually operated plunger, often found on carburetors
Primer
This is a flat, springy valve covering ports between the carburetor and the crank chamber in a 2-cycle engine
Reed
If the float is set too high in a float-type carburetor, the engine will run
Rich
As the air filter fills with dirt, the air-fuel mixture will become
Richer
When closed, does the choke provide a leaner or richer air-fuel mixture, which is needed to start a cold engine
Richer
How can one tell if an engine reed is leaking
Run the engine while holding a clean strip of paper about 1 inch above carburetor throat. If paper becomes spotted with fuel, the reeds are not seating properly
Why should the throttle plate screws and the choke plate screws be replaced with new ones when assembling a carburetor
Screws are treated with a dry adhesive to secure them
The diaphragm needle valve must fit the seal properly, so that it ________ when it is closed
Seals
The percent of speed change required to produce a corrective movement of the fuel control mechanism
Sensitivity
On some carburetors, the amount of fuel that enters the main discharge nozzle is regulated by
The Float Level
Richest air-fuel mixture takes place during
The starting of the engine
This controls speed by regulating the amount of fuel delivered to the engine
Throttle
Why should low-pressure compressed air be used instead of a rag or paper towel to dry carburetor parts
To avoid lint contamination
What is the purpose of the carburetor float
To maintain a constant level of fuel in the float bowl
When installing a new inlet needle seat, the smooth side of the seat should be installed towards or away from the inlet needle
Towards
A _______ in the float bowl is used to equalize the air pressure above the fuel in the float bowl and the air pressure the carburetor
Vent
A carburetor is said to be this when it has openings that allows some air to enter even when it is closed
Vented
What is a restriction in a passage, which causes incoming air to increase in velocity called
Venturi
Before making fine adjustments to a carburetor, the engine should be
Warmed up
The choke shaft, throttle shaft, and bearing holes should be examined for what
Wear