Use of the Strangler

All our cars are fitted with carburettor air stranglers, to facilitate starting the engine when cold.

As is well-known, the strangler consists of a mechanism which restricts the air intake of the carburetter, thus causing the engine to exert a much greater suction over the jets; consequently, the engine sucks into the cylinders a mixture, in which there is an excess of petrol in liquid form.

Whilst the engine is being started, the speed at which it is turning round is very low, and the tiny amount of liquid petrol that is sucked into the cylinders, is not of sufficient volume to do any harm.  If, however, the strangler is still kept shut, or partially shut, after the engine has started, and the number of revolutions of the engine is fairly high, the amount of liquid petrol that is drawn into the cylinders is sufficient to wash the lubricant from the cylinder walls, with the consequence the pistons become partially seized and badly scored.

On most of our cars, stops have been provided in order that the strangler could be locked in a shut or semi-shut position.  This was done in case it should become necessary to start the car by means of the starting handle, and not by the starter motor.  Experience has shown us, however, that many owners do riot realise the danger of excessive use of the strangler, and in order to ensure a quick get-away on the road are in the habit of driving the car until it gets thoroughly warm with the air strangler locked in the semi-open position.  As a result some owners have caused damage to the pistons of their engines, necessitating the fitting of a new set of pistons.

In order to avoid this danger, we are arranging to make all strangler controls without any means of locking them in a shut, or partially shut position, so that the strangler can only be operated by actually holding it out.  In all cases that come under our notice, where pistons have suffered through this abuse of the strangler, we are taking the strangler control to pieces, and removing the small stop peg, and we would suggest that our Agents circularize their clients, and where they think there is any danger of abuse of the strangler, they also remove this peg.

Our remarks are very appropriate at this time of the year, as, the mornings generally being cold, car owners are usually anxious to get away as quickly as possible, and as they find they can do so by means of the strangler, they use it in ignorance of the damage they are doing to their engines.

These remarks apply particularly to the Austin Sixteen, as being a 6-cylinder with cylinders of fairly small bore and a long induction pipe, a slightly longer time is taken in warming up the induction passages.

We hope all our Agents will pay particular attention to this, as it is to our mutual interest that owners should nor experience trouble with their engines, through not thoroughly understanding exactly what is happening in the engine, when the strangler is in operation.

From Austin Technical Sheets