The British Seagull® Amal Two-Jet carburettor power jets that control the amount of fuel to oil ratio used to run the engine. There are various power jets used on the Amal Two-Jet carburettors fitted to the British Seagulls and each jet has a number on one of the four flat surfaces for identification.
British Seagull Outboard engines with the Amal Two-Jet carburettor were fitted with a Power Jet (45) for the fuel to oil ratio of 10:1; from the beginning of manufacture to 1978.
British Seagull outboards fitted with an Amal Two-Jet carburettor from 1978 were fitted with a Power Jet (40) for the fuel to oil ration of 25:1.
Each Power Jet is interchangeable depending on the fuel ratio required, so, engines fitted with a 10:1 power jet (45) can be switched to running on a 25:1 mixture by replacing the power jet to a size 40; and vice versa.
Always use unleaded petrol and good quality marine outboard two-stroke oil (not motorcycle or agricultural oil). If your engine is to be used for very few occasions per year it may be more beneficial for the engine to continue to use the original 10:1 ratio.
This part is suitable for all British Seagull Outboard engines fitted with the Amal Two-Jet Carburettor including: AC, AD, AHC, TC, TD, THC, WC, WD, WHC, S, WS, WSC, SP, SPC & WSPC.