Gwynne pump Mountnessing/Marconi Copyright Malcom Batten. Used with permission.. photo at Peterborough rally
1922 appliance. Exhibited in the Coventry Motor Museum...this light pump was built by the Gwynne Company of London ....and was a demonstrator...it was later sold to the Mountnessing village fire brigade in Essex. In 1939 it was passed on to the works FB of Marconi at Chelmsford. During a night of heavy bombing during WW2, this little fire engine helped save the machine, paint and carpenters workshops by pumping water at the rate of 350 gallons per minute for no less than 24 hours.
In 1955 the pump was on display at Essex Fire Brigade HQ at Brentford. 14 years later it was restored by apprentices from Marconi Ltd and is now at Coventry since 2000.
The 950cc engine is rated at 8hp and will pump water at 100gpm at 100psi at an engine speed of 3000rpm
source of info below

Picture added on 02 March 2025 at 20:15