There could be several reasons why a Motorcraft 2100 carburetor is hard to start:
- Fuel System Issues: Problems within the fuel system, such as a clogged fuel filter, a faulty fuel pump, or restricted fuel lines, can result in inadequate fuel delivery to the carburetor, making it hard to start.
- Bad or Clogged Accelerator Pump: When cold the engine needs an extra squirt of fuel to get going. This is accomplished by the accelerator pump. Look down the carburetor and pump once. You should see gas squirting out in 2 places. If not, then the either the accelerator pump circuit is the problem, or the isn't enough fuel left in the fuel bowl.
- Vacuum Leaks: Vacuum leaks around the carburetor base gasket, intake manifold gaskets, or vacuum hoses can disrupt the proper operation of the carburetor, affecting starting performance.
- Ignition System Faults: Problems with the ignition system, such as worn spark plugs, faulty ignition coil, or a malfunctioning distributor, can cause weak or inconsistent spark, making it hard to start the engine.
- Choke Malfunction: A malfunctioning choke mechanism, whether it's not closing properly when cold or not opening fully when warm, can affect the air/fuel mixture during startup, leading to difficulty in starting.
- Engine Timing: Incorrect ignition timing can result in the engine firing at the wrong moment, making it harder to start or causing it to run poorly once started.
- Cold Weather Issues: In colder temperatures, the engine may require richer fuel mixture and a properly functioning choke to start smoothly. If these conditions aren't met, starting difficulties may occur.
- Mechanical Wear and Tear: Over time, components within the carburetor, such as the float assembly, accelerator pump, or throttle linkage, can wear out or become damaged, affecting the carburetor's ability to function properly.
- Moisture or Contamination: Moisture or contaminants in the fuel system can lead to issues such as fuel degradation, corrosion, or blockages, all of which can contribute to starting problems.
- When Hot: Hard starting after running a hot engine could be caused by fuel getting siphoned out of the fuel bowl. After turning off the engine look down the carburetor to see if gas is dribbling from the venturi. Another possibility is that after turning off a hot engine, the gas boils out of the carburetor. This is called percolation. Cooling down the fuel is the answer here.
Addressing these potential issues through proper maintenance, tuning, and troubleshooting can help improve the starting performance of a Motorcraft 2100 carburetor-equipped engine.
You Have To Close The Choke Valve by Hand
- Do you press the gas once to allow the fast idle to set and relax the choke linkage?
- The thermostat may not be set. With the throttle open, twist the thermostat until the choke valve closes, then give it another 1/8 turn to preload.
- Move the choke valve open and closed to feel any binding.
Hard Starting after engine is warmed up.
If this was a problem before tinkering with the carburetor, then make sure the electrical system is in good shape. The carburetor is blamed for many problems when in fact the electrical system is most likely at fault.
Check to make sure the choke valve is open completely when warmed up. If it isn't opening, then the fuel mixture will be too rich for starting.
This could be due to gas leaking into the engine after the engine is turned off, or at idle.