4. POOR IDLE OR NO IDLE & STALLING
a) All the items listed under hard starting.
b) Mounting gasket improperly installed.
c) Heat riser valve operation. & EGR sticking
d) Vacuum leaks. Check all diaphragms including vacuum advance on distributor should hold vacuum when suck on. Manifold leaks, brake booster, PCV valve not working properly.
e) Idle mixture and speed adjustment should be set to vehicle manufactures specifications. Check for flooding through venturie’s secondary shaft when slightly open.
f) NO IDLE – blocked idle jet, idle solenoid not working or incorrect voltage.
Double wire solenoids can have bad earth through wiring system
It is nearly impossible for a carburettor to cause a vehicle backfire. 90% of carburettor problems are caused by electrical faults. Make sure that the plug wires are properly and correctly attached. Check ignition voltage to and from t he coil and complete ignition system including the ignition switch, distributor cap and rotor. A bad vacuum leak can cause a mixture to lean out enough to cause an engine to backfire. Check the manifold vacuum with a vacuum gauge, this can show many engine faults, leaking, burned or stuck valves, a worn camshaft or timing gears, incorrect valve settings.
6. HESITATION OR STUMBLE, SURGING ON TAKE OFF.
a) Check for proper EGR operation.
b) The EGR should be closed at idle and when engine is cold.
c) Check the distributor and timing, make sure the distributor advanced mechanism and vacuum advance is functioning properly.
d) Check manufactures specifications and check again for vacuum leaks. Check accelerator pump linkage is not bent or out of adjustment from shipping or installation.
e) Check accelerator pump discharge inside the carburettor is strong and consistent. Some leather accelerator pump caps must be soaked for about 12 hours to function properly, especially if used with LPGAS.
f) Check for clogged air filter and weak fuel pump.
g) Check for clogged exhaust system, check carbon canister and carby venting. Check fuel tank venting systems.
h) Carburettor may require re-jetting to suit your particular engine.
7. POOR PERFORMANCE OR GAS MILEAGE.
a) All items under POOR IDLE.
b) Clogged or inoperative gas tank venting carbon canister blocked.
c) Dragging brakes.
d) Clogged air filter.
e) Low tyre pressure.
f) Automatic transmission malfunction.
g) Wrong or malfunctioning thermostat.
h) Choke not opening completely when engine is warm.
i) Restricted exhaust system.
j) Incorrect fuel mixtures, carby may require rejetting to suit individual engine.
k) Faulty distributor and ignition systems.
l) Poor driving habits.
NOTE: When fitting a restored carburettor to an engine in poor condition and tune or with a weak electrical system it may cause it to run less efficiently or worse. Total combustion relies on a good strong spark to burn lean and efficient.
Weak spark = Rich mixture = Poor running
If all else fails call helpline 89474748
DO NOT attempt to dismantle carby.
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