OVERCOMING HESITATION
Q My 1980 Cortina 1600 has a Weber 32/36DGV carburettor. It’s developed a bad hesitation when setting off from rest and when opening the throttle wide on the move. What might be wrong? Eric Greenhalgh, Wigan A Check the ignition timing is correct, that the vacuum advance holds vacuum when you suck the tube and cover the end with your tongue, and that the rotor arm springs smartly back when twisted (while holding the points off the cam). Ensure the carburettor float level is correct. Hold the carburettor top vertical with the float just resting on the sprung ball of the valve. There should be 41mm between the gasket face and the top of the float if it’s brass, or 35mm if it’s plastic. Make sure the accelerator pump nozzle delivers a smart jet, whether the throttle’s just being tickled or snapped open. Blow out the jets while you’re there, plus the filter on the fuel inlet. Check that the secondary throttle butterfly closes fully.
There should be a heatproof spacer between the carburettor and the inlet manifold. Check that it’s present and the gaskets on each side are in good order. Make sure it hasn’t distorted and place the carburettor on a sheet of plain glass to check that the flange at the base isn’t warped. Look for a perished servo hose or defective servo seals. Blank off the servo stub on the inlet manifold and go for a test-drive, remembering the brakes will be less responsive. Finally, make sure the valve clearances aren’t over-tight.