Cold-start worry

Q I have a 1993 Honda Civic 1493cc saloon fitted with a carburettor that refuses to start when it’s cold. When I do get it going, it’s perfect. When warm or hot, it starts with no problem. When it’s cold, I have to put the throttle right down to the floor and it will just about start before the battery goes dead. There is a spark and fuel is getting to the cylinders – number 4 cylinder was flooded but number 1 cylinder was dry. If it has been left on the driveway for nine hours it just about starts without touching the throttle. But if I leave it for 15-20 hours it won’t start and I have to follow the process in the Honda manual, but then it seems to get flooded.

Nigel Thatcher

A My first thought is that the choke mechanism may not be operating correctly, but the fact that you have one spark plug which flooded means that it appears as though sufficient fuel is reaching the combustion chamber.

If the spark plugs are in good order, one possibility is that the cylinder compressions are below par. It may be worth carrying out a compression test to ensure this is not the case. Theoretically, if the spark plug is firing and fuel is entering the cylinder, then ignition should take place. Alternatively, it may be the case that the engine is being flooded by a faulty carburettor, and as the engine runs well when it does start, the most likely culprit is the needle valve in the float chamber. This may simply need adjusting, but given the age of the vehicle, a new needle valve may be required to prevent excess fuel leaking into the inlet manifold. If this is the case, fitting a carburettor overhaul kit may be the best solution.