I have one of the 120cc Mk 12 engines on an old Finsbury all cast iron self priming pump......the motor runs a bit smokey ,but will run all day if fuel is kept up,and I used it for pumping oily water from a fuel and oil tank bund ......bit silly really ,you have to have a bund to stop oily water escaping,then after a storm ,pump it all out on the roadway to disperse as it may....Anyhoo ,i built the motor and pump from bits ,no money spent,and even tho the spark is so weak as to be invisible ,it starts straight away and runs perfectly......Incidentally ,for years Finsbury were agents for both Villiers and JAP engines of all kinds,and the Finsbury depot in Brisbane had a Villiers twin two stroke from a car mounted as a display.