Chapter 1 Routine maintenance and servicing
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Chapter 1 Routine maintenance and servicing

Chapter 1 Routine maintenance and servicing Chapter 1 Routine maintenance and servicing

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11.07.2015 Views

1595Ford Fiesta Remake4A•14 Fuel system – carburettor engines29.5 Choke pull-down assembly (A) andfuel feed filter housing (B) (Weber DFTMcarburettor)A Manual choke assemblyB Choke vacuum pull-downC Secondary idle jetD Secondary barreldiaphragm assemblyE Idle speed adjustingscrew29.3 Exploded view of the carburettor (Weber DFTM)F Idle mixture adjustingscrewG Accelerator pumpassemblyH Throttle kickerJ Power valve diaphragmK Float29 Carburettor (Weber DFTM) -dismantling, cleaning,inspection and reassembly4Note: Refer to the warning note in Section 1before proceeding. Check parts availabilitybefore dismantling. If possible, obtainan overhaul kit containing all the relevantgaskets, seals, etc, required for reassemblyprior to dismantling the carburettor.Dismantling1 With the carburettor removed from theL Primary main jet combinedassemblyM Primary idle jetN Needle valveP Fuel feed filterQ Secondary main jetcombined assemblyvehicle, prepare a clean, flat work surfaceprior to commencing dismantling. Thefollowing procedures may be used for partialor complete dismantling, as required.2 Clean the exterior of the carburettor anddetach all vacuum pipes (where applicable),having noted their fitted location for correctsubsequent reassembly.3 Remove the six screws securing thecarburettor upper body, and detach it.Discard the gasket (see illustration).4 Dismantle the carburettor upper body asdescribed in the following paragraphs.5 Remove the three screws securing thechoke pull-down diaphragm and detach it(see illustration).6 Unscrew the brass nut adjacent to the fuelfeed connection, and remove the fuel feedfilter.7 Tap out the float retaining pin, then detachthe float and needle valve.8 Unscrew and remove the needle valvehousing.9 Dismantle the carburettor main body asdescribed in the following paragraphs.10 Remove the main and idle jets, havingnoted the size and fitted location of each oneto ensure correct subsequent reassembly.Note that the main jets are a combinedassembly incorporating air correction jets andemulsion tubes. Carefully prise out theaccelerator pump discharge tube.11 Detach the throttle kicker and itsmounting bracket assembly.12 Remove the anti-dieseling (fuel cut-off)solenoid.13 Remove the four screws securing theaccelerator pump assembly, and dismantlethe assembly noting the fitment of itscomponents (see illustration).14 Disconnect the secondary barreldiaphragm operating rod by pulling the lowersection of rod downwards and twisting torelease it from its retaining socket. Remove itsfour cover retaining screws and dismantle theassembly (see illustration).15 Undo the three screws securing thepower valve assembly and remove itsdiaphragm (see illustration).29.13 Accelerator pump renewal(Weber DFTM carburettor)A Diaphragm B Housing (cover)29.14 Exploded view of the secondarybarrel diaphragm assemblyA Diaphragm C Operating rodB Return spring29.15 Exploded view of the power valveassembly (Weber DFTM carburettor)A Vacuum gallery B Diaphragm

Fuel system – carburettor engines 4A•1516 Prise out the tamperproof seal coveringthe fuel mixture screw, then undo and removethe mixture screw.Cleaning and inspection17 Wash the carburettor components,drillings and passages with clean petrol, thenblow them dry using a low-pressure air line. Ahigh-pressure air line must not be applied tothe accelerator pump discharge assembly orthe pump supply valve, as they each contain arubber Vernay valve, and these can easily bedamaged under high pressure. Never use apiece of wire for cleaning purposes.18 Examine all of the carburettorcomponents for signs of damage or wear,paying particular attention to the diaphragms,throttle spindle and plates, needle valve andmixture screw; the power valve jet is adjacentto the primary main jet. Renew alldiaphragms, sealing washers and gaskets asa matter of course.Reassembly19 Refit the fuel mixture screw by fullywinding the screw in, then unwinding threeturns to give an approximate setting.20 Refit the power valve assembly ensuringthat the diaphragm lies flat, and that thevacuum gallery lines up correctly with thediaphragm and housing.21 Reassemble the secondary barreldiaphragm into its housing, ensuring thatthe diaphragm lies flat and that the vacuumgallery lines up with the diaphragm andhousing. Also, to assist with installation, donot reconnect its operating rod until the coverhas been secured.22 Refit the throttle kicker mounting bracket.23 Refit the anti-dieseling (fuel cut-off)solenoid, using a new sealing washer.24 Refit the accelerator pump assembly,ensuring that the diaphragm lies flat and is notkinked.25 Reassemble the throttle kicker, ensuringthat the diaphragm lies flat and that therelative position of the diaphragm operatinglink to the throttle kicker cover is correct. Fullyattach the throttle kicker assembly.26 Refit the main and idle jets, makingreference to the notes taken duringdismantling to ensure correct fitted locations.27 Reassemble the carburettor upper bodyas described in the following paragraphs.28 Refit the needle valve housing (using anew washer if applicable).29 Refit the needle valve and float assembly,having ensured that the float tag locatesbelow the spring clip on the needle valve.Insert the float retaining pin to secure.30 Adjust the float level as follows. Ensuringthat a new gasket is fitted to the carburettorupper body, hold the upper body in thevertical position; the needle valve must beshut off. Measure the distance shown (seeillustration), and adjust by bending the floattag if the measurement is outside thespecification. Recheck the float leveladjustment after bending the float tag, asnecessary.31 Refit the choke pull-down diaphragm,ensuring that the diaphragm lies flat and thatthe vacuum gallery lines up correctly with thediaphragm and housing (see illustration).32 Adjust the choke pull-down as follows.Fully close the choke, then manually push thediaphragm operating rod up to its stop;measure the distance between thedowndraught side of the choke plate and theventuri, using a gauge rod or the shank of atwist drill bit (of known size). If themeasurement is outside specification, removethe tamperproof seal from the housing, andadjust the now revealed adjustment screwaccordingly. Fit a new tamperproof seal aftersuccessful adjustment.33 Refit the fuel feed filter, and secure withits brass nut and sealing washer.34 Refit the carburettor upper body to thecarburettor main body, ensuring that its newgasket seats correctly and that the float doesnot foul during assembly. Insert and tightenthe securing screws.35 Reconnect any vacuum pipes removedduring dismantling (where applicable).36 On completion, refit the carburettor asdescribed in Section 28. Where applicable,check and adjust the throttle kicker setting(Section 27) after adjusting the idle speed andmixture settings.30 Carburettor (Weber TLD) -descriptionThis carburettor incorporates many of thefeatures of the TLDM type described inSection 18. The main differences are that athrottle kicker is not used, the secondaryventuri (barrel) is vacuum-operated, and that acoolant-heated automatic choke controlsystem is fitted.The choke system is fully automatic. Whenthe engine is cold, the bi-metal spring whichcontrols the position of the choke plate is fullywound up, and holds the plate closed. As theengine warms up, the bi-metal spring isheated by the coolant and begins to unwind,thereby progressively opening the chokeplate. A vacuum-operated pull-downmechanism controls the choke plate undercertain operating conditions, and an internalfast-idle system is incorporated.Idle speed and mixture adjustmentprocedures are described in Chapter 1, but itis important to note that accurate adjustmentscan only be made using the necessaryequipment.31 Carburettor (Weber TLD) -fast-idle speed adjustment 4Note: Before carrying out any carburettoradjustments, ensure that the spark plug gapsare set as specified, and that all electrical andvacuum connections are secure. To carry outchecks and adjustments, an accurate4A29.30 Float level adjustment (Weber DFTMcarburettor)A Float level setting dimensionB Adjusting tag29.31 Exploded view of the choke pull-down assembly (Weber DFTM carburettor)A Housing B Diaphragm1595Ford Fiesta Remake

1595Ford Fiesta Remake4A•14 Fuel system – carburettor engines29.5 Choke pull-down assembly (A) <strong>and</strong>fuel feed filter housing (B) (Weber DFTMcarburettor)A Manual choke assemblyB Choke vacuum pull-downC Secondary idle jetD Secondary barreldiaphragm assemblyE Idle speed adjustingscrew29.3 Exploded view of the carburettor (Weber DFTM)F Idle mixture adjustingscrewG Accelerator pumpassemblyH Throttle kickerJ Power valve diaphragmK Float29 Carburettor (Weber DFTM) -dismantling, cleaning,inspection <strong>and</strong> reassembly4Note: Refer to the warning note in Section 1before proceeding. Check parts availabilitybefore dismantling. If possible, obtainan overhaul kit containing all the relevantgaskets, seals, etc, required for reassemblyprior to dismantling the carburettor.Dismantling1 With the carburettor removed from theL Primary main jet combinedassemblyM Primary idle jetN Needle valveP Fuel feed filterQ Secondary main jetcombined assemblyvehicle, prepare a clean, flat work surfaceprior to commencing dismantling. Thefollowing procedures may be used for partialor complete dismantling, as required.2 Clean the exterior of the carburettor <strong>and</strong>detach all vacuum pipes (where applicable),having noted their fitted location for correctsubsequent reassembly.3 Remove the six screws securing thecarburettor upper body, <strong>and</strong> detach it.Discard the gasket (see illustration).4 Dismantle the carburettor upper body asdescribed in the following paragraphs.5 Remove the three screws securing thechoke pull-down diaphragm <strong>and</strong> detach it(see illustration).6 Unscrew the brass nut adjacent to the fuelfeed connection, <strong>and</strong> remove the fuel feedfilter.7 Tap out the float retaining pin, then detachthe float <strong>and</strong> needle valve.8 Unscrew <strong>and</strong> remove the needle valvehousing.9 Dismantle the carburettor main body asdescribed in the following paragraphs.10 Remove the main <strong>and</strong> idle jets, havingnoted the size <strong>and</strong> fitted location of each oneto ensure correct subsequent reassembly.Note that the main jets are a combinedassembly incorporating air correction jets <strong>and</strong>emulsion tubes. Carefully prise out theaccelerator pump discharge tube.11 Detach the throttle kicker <strong>and</strong> itsmounting bracket assembly.12 Remove the anti-dieseling (fuel cut-off)solenoid.13 Remove the four screws securing theaccelerator pump assembly, <strong>and</strong> dismantlethe assembly noting the fitment of itscomponents (see illustration).14 Disconnect the secondary barreldiaphragm operating rod by pulling the lowersection of rod downwards <strong>and</strong> twisting torelease it from its retaining socket. Remove itsfour cover retaining screws <strong>and</strong> dismantle theassembly (see illustration).15 Undo the three screws securing thepower valve assembly <strong>and</strong> remove itsdiaphragm (see illustration).29.13 Accelerator pump renewal(Weber DFTM carburettor)A Diaphragm B Housing (cover)29.14 Exploded view of the secondarybarrel diaphragm assemblyA Diaphragm C Operating rodB Return spring29.15 Exploded view of the power valveassembly (Weber DFTM carburettor)A Vacuum gallery B Diaphragm

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