CARBURETTOR WITH DRAIN PORT

Abstract: A carburettor 8 especially useful for an outboard motor 2, where there is a risk of water ingress and fuel contamination, has the conventional drain plug on lower drain port 9 replaced by tubing 10 with a closure knob 11, below the carburettor. The length of closed tubing fills with fuel as the engine oper­ ates. If water enters the carburettor intake 8a, opening of closure 11 drains this accumulated fuel, and the carburettor chamber, under gravity; drainage is improved if the outlet end 13 of the tubing is lower still.

Description: THIS INVENTION relates to adaptation of an outboard motor to permit restarting of the engine as soon as possible after the carburettor chambers have been flooded with water. An internal-combustion engine for a land vehicle is normally not designed in any way for contact with, or immersion in, a body of water. Should such immersion occur as the result of an accident the engine stops, becomes flooded with water, and needs specialist attention thereafter. A few vehicles have on-land/in-water capability, e.g. tanks. They typically have fully shielded engines, with sealed housings and special exhaust and inlet ports. This is an expensive expedient, and for waterborne craft attempts have been made to protect the engines especially outboard engines against casual splashes, temporary immersion (wave action) or longterm immersion (e.g. capsize) by a selectively sealable carburettor air intake. Moreover, our copending Patent Application 8524232 of even date entitled "INTERNAL COMBUSTION ENGINE AIR INTAKE" proposes a further modification in which the air intake is extended by an elongate duct the configuration of which and/or the air inlet location of which and/or the nature of the air inlet end of which is such as to protect the carburettor against flooding by water during partial or total immersion of the motor. All of the above expedients set out to prevent access of water to the interior of the engine, and especially to the carburettor. However, we have realised that, especially for a smaller engine, the cost of even the cheapest expedient can be relatively significant. An example of an engine with specially designed features for draining an engine after it has been flooded is described in U.S. Patent No. 4,461,250. This disclosure involves a specially modified manifold and a complicated arrangement of conduit means coupled to a valve. In order to drain the engine once flooded, it is necessary to remove the engine from the water. Then, the valve is opened and the water drained through the conduit means from the various parts of the flooded engine. This arrangement does not fully expunge the engine of contaminated fluid and so further measures are required such as purging the contaminated fluid by pumping fresh fuel through the conduit means. This type of drainage suffers from the disadvantages that it is complicated; expensive to manufacture; does not provide efficient drainage; and most importantly necessitates the engine being removed from the water before the drainage operation can be effected. In rough sea conditions, it is necessary to drain the engine and replace the spark plugs as quickly as possible in order to restart the engine. In many situations it would not be possible to remove the engine from the water and much too time consuming to open the valve and drain contaminated fuel, flush through fresh fuel and replace dry spark plugs. The present invention therefore sets out to achieve a means by which an engine flooded with water can be rapidly cleared and restarted. It has particular utility in, but is not limited to, the smaller end of the range of outboard motor sizes. The present invention envisages an attachment to a conventional carburettor. Typically, these define a chamber to hold a quantity of petrol. At the base of the chamber is a threaded port with a threaded sealing plug therein. Even some land vehicles possess such carburettor drain ports, for instance for use in the event of water in the fuel or similar mishaps. Outboard motors possess such carburettor drain ports for use more typically when water has entered the carburettor via contaminated fuel in the air intake duct. It is not unknown for craft fitted with such motors to capsize e.g. on a rescue or assault mission in adverse weather. The vessel is designed (or provided with) a self righting capability but by the time this has come into use the motor is typically full of water, even though mercury gravity switches switch off the motor after a given angle of capsize. It is difficult in adverse weather, often at night, to remove the engine housing, locate and remove the drain port plugs (especially since these are usually located in the expection that the engine will be back on the bench at the repair shop before such steps are taken and are therefore not easily accessible ) and drain the small carburettor chamber effectively, in heavy seas with waves splashing the stationary craft. According to the present invention there is provided a outboard motor having an internal combustion engine comprising: a carburettor which includes a carburettor body chamber having an upper portion and a lower portion; means defining an air intake in said carburettor body chamber; and a carburettor drain port said port being permanently open and located towards the lower portion of the carburettor body chamber; a first length of tubing communicating with said open carburettor drain port which at least partially fills with liquid when the engine is running; a manually operable, externally accessible, normally closed but selectively operable closure means communicating with said first length of tubing, said closure means located beneath said drain port to arrange said first length of tubing to extend downwardly from said drain port to said closure means; a second length of tubing communicating with said closure means having a drainage end; characterised in that: said air intake means is located in said upper portion of said carburettor body chamber; and in that said drainage end of said second length of tubing is located beneath said closure means such that when said closure means is open the liquid in said first tubing drains out through said drainage end for effecting gravity drainage of liquid in said carburettor body chamber. The drainable ducting is preferably a flexible synthetic polymer tube, controlled by a turnable knob as a tap to achieve drainage. An internal combustion engine comprising two or more carburettors modified as above is also an aspect of the present invention. Also the closure means e.g.knobs, can be mounted on the fascia in an accessible forward position. The invention will be further described with reference to the single Figure of the accompanying drawing, which shows a modified single carburettor system and its location in relation to an outboard motor. An outboard motor comprises a tray 1 upon which is mounted an engine 2 shown diagrammatically as block (in dotted lines) with a starter pulley 3 (and cord 4) on top. Beneath and integral with tray 1 is a rudder 5 enclosing a drive between the motor 2 and the propeller 6. A lid or housing 7 fits over the motor, and onto the tray 1 generally by simple clips. At the forward end of the motor is located a carburettor 8 air intake generally at an upper location 8a and with a conventional drain port 9 at its lower end. However, in place of a threaded fitting there is fixed a flexible polymer tube 10, passing to control knob 11 suitably positioned on fascia board 12 of tray 1. The knob 11 is generally below the level of drain port 9, and the outlet from the drain port at 13 is lower still. Instead of the one carburettor shown, two, three, four or more carburettors can be used, each equipped with a suitable drainage length of tubing 10. Separate knobs 11 can be used in such a case, or the drain tube can be combined to only one or two such knobs for joint drainage. The use of such a fitment is as follows:- Initially the engine 1 is running normally. As the craft (e.g. an inflatable dinghy) capsizes, the engine stops due to a cutout switch based on gravity flow of mercury in a constricted container. The vessel is righted, in itself a standard emergency procedure . The lid or cowling 7 is removed, and excess water drains away. The fuel line is removed, and knob 11 is unscrewed. It is of course readily accessible to the operator and does not need tools for its use. Moreover, we have found that the length of tubing 10 above the knob 11 fills with petrol in use; thus, when the knob 11 is opened this length of full tubing drains and draws out the liquid from the carburettor. Draining the carburettor in this way is more efficient for emptying the carburretor chamber than simple drainage through a drain port, and is effected without inconvenient removal of threaded drain port plugs. The engine spark plugs are then removed, and the engine turned over by pulling cord 4. This expels water from the engine cylinders through the spark plug openings. Twenty pulls or so may be necessary. The fuel line is reconnected to flush the carburettors, the fuel used being drained through tube 10 until no water remains therein. The fuel valves are closed, the engine primed, choke pulled out, new dry plugs fitted, and the engine should restart.

Claims: An outboard motor having an internal combustion engine (2), comprising: a carburettor (8) which includes a carburettor body chamber having an upper portion (8a) and a lower portion; means defining an air intake in said carburettor body chamber; and a carburettor drain port (9), said port being permanently open and located towards the lower portion of the carburettor body chamber; a first length of tubing (10) communicating with said open carburettor drain port (9) which at least partially fills with liquid when the engine is running; a manually operable, externally accessible, normally closed but selectively operable closure means (11) communicating with said first length of tubing (10), said closure means located beneath said drain port to arrange said first length of tubing (10) to extend downwardly from said drain port (9) to said closure means (11); a second length of tubing (10) communicating with said closure means (11) having a drainage end (13); characterised in that: said air intake means is located in said upper portion of said carburettor body chamber; and in that said drainage end (13) of said second length of tubing is located beneath said closure means (11) such that when said closure means is open the liquid in said first tubing drains out through said drainage end (13) for effecting gravity drainage of liquid in said carburettor body chamber. An outboard motor as claimed in claim 1, in which the first and second tubing each comprises a flexible synthetic polymer and the closure means is a turnable knob (11). An outboard motor as claimed in claim 1 or 2, comprising two or more carburettors, two or more closure means and two or more first lengths of tubing, each first length of tubing coupled to a respective carburettor and each communicating with a respective closure means. An outboard motor (2) as claimed in any one of claims 1 to 3, in which the closure means is or are mounted on a fascia member (12) of said motor (2) so as to be located in an accessible position from the vessel.

Inventors: GLEN, ROBERT D.
Applicants: E.P. BARRUS LIMITED
Application year: 1986
Main classification: F02M19
IPC codes: F02M19, F02B61