The two permissible colors for neutral conductors, according to the NEC, are white and gray.
First, before you do anything else... Find and verify the colours for Live, Neutral and Earth for both nation's standards. (Respectively Brown, Blue and Green/Yellow-striped in the UK). (I don't know the Australian colours.)Then remove the Australian plug - presumably there is an earth contact of come sort, trim the wires to the correct length and fit the UK plug.NOW VERIFY CORRECT CONNECTIONS BEFORE PLUGGING IT INTO THE MAINS!
In a 2-pin plug, the wire that is not present is the grounding wire. This type of plug only has two prongs for the live and neutral wires, unlike a 3-pin plug that includes a grounding wire for added safety.
Neutral switch
In a 6-30 3 prong female plug, there are two hot wires, which are usually black or red, and these connect to the two hot terminals. The neutral wire, typically white, connects to the neutral terminal, and the green wire, which is the ground wire, connects to the ground terminal.
The neutral wire completes the circuit and carries the current back to the power source. It provides a path for the electricity to return safely to the earth or ground. In a 3 pin plug, the neutral wire is usually color-coded as blue.
There should be 2 or 3 wires. A hot, a neutral and sometimes a ground.
coil-----3---4 pack----2---6 plug-----1---5
The 1999 model, 90 hp Mercury outboard requires an NGK BUHW-2 spark plug, standard plug wires are acceptable.
The spark plug wiring is fairly simple; first note that cylinders are labelled 1 - 4 from left to right while sitting on the seat facing forward. There is a coil for cylinders 2 & 3 and a coil for cylinders 1 & 4. The spark plug wires normally have a tag labelled 1- 4 on them but if not see below. * coil for # 2 & 3 cylinders have the two spark plug wires that are normally closest in length - the wires do not have an order as long as the come from the 2/3 coil and can reach the 2 & 3 cylinder. * coil for # 1 & 4 cylinders will have either two wires that are longer than the wires on the 2/3 coil or one really long spark plug wire and one short spark plug wire. The spark plug wires also do not have an order as long as they reach the spark plugs.
coil----3---4 pack---2---6 plug----1---5
The left coil wires go to 1 and 4 the the right coil wires go to 2 and 3.
The reserve lights are light green and dark blue, you will find them on one plug with only those to wires attached to a white block on the steering column about 2 to 3 inchs from the firewall inside the car. The "neutral safety switch" in mechanical so there are not wires persay, but there are other ways to wire one in.