Tuesday 13 March 2012

Instruction Manual

Congratulations on taking ownership of your new worn-out and modified Atco cylinder lawn mower. A few decades spent familiarising yourself with the operation and maintenance of the machine will pay dividends in the coming months.

The machine is fitted with a seriously worn Briggs&Stratton Villiers F6 two stroke engine which should have been thrown away in the 1970s. It will provide rattly and unreliable power to both the cutting blades and the roller.

  1. Charge the battery.
    The magneto failed in the early 2000s and was replaced by a lead-acid battery and a dc coil. There is no charging system fitted to the mower. Connect the battery to the charger and turn the charger on at the mains. You will notice an old light bulb soldered precariously into the charging circuit. This provides both a visual indication that the battery is being charged, and some degree of current limiting.
  2. Mix the fuel
    The annotations of the correct fuel mixture have been illegible for many years, instead use the black mark on the greasy polythene jug (supplied with the mower) to measure the petrol. Use the scratch on the side of the 35mm film canister (supplied with the mower) to measure 2-stroke oil.
  3. Fill the fuel tank
  4. Food the carburettor
    Open the fuel tap. Depress the float valve override until fuel drips out of either the venturi or the float chamber. If fuel does not drip out, proceed to the section "Rebuild the carburettor"
  5. Prime the engine
    Ensure that the ignition switch is OFF. Set the throttle to 75%. Fully close the choke. Briskly pull the starting handle twice. The kick start wore out in the 1980s and was replaced by a large pulley and a length of sturdy cord.
  6. Start the engine
    Turn the ignition switch to ON. Set the throttle to 25%. Open the choke a crack. Briskly pull the starting handle twice. In the unlikely event that the engine fires you should instantly start operating the choke and throttle such that the engine neither stalls nor floods. If the engine is now running proceed to the section "Cutting the grass"
  7. Rebuild the carburettor
    The machine is mainly assembled with whitworth fasteners, except for the ones which wore out in the 1970s and 1980s which were replaced with A/F fasteners. Fasteners replaced in the last 20 years are mainly metric. The kit of tools (supplied with the mower) contains both pre-war and post-war whitworth spanners so their markings don't correspond with the fastener dimensions.
    You should usually only need to bebuild the carburettor once or twice for each lawn that you mow.
    Disconnect the fuel hose from the float chamber. Withdraw the carburettor from the crankcase spigot. The carburettor body is deformed and the spigot is corroded so it is very difficult to remove the carburettor. Remove the float chamber. The set screw which holds the main jet in place has stripped so the main jet should now have fallen out. clear the main jet, reseat the needle in the float valve, clean the float chamber and reassemble the carburettor.
  8. Cut the grass
    The clutch lining is absolutely irreplaceable so operate the clutch as little as possible. In particular you may not open the clutch to turn corners or to turn around at the end of a run. The tick-over adjustment is broken, instead simply try not to close the throttle so far that the engine stops. Open the throttle a little to increase engine revs and close the clutch. Cut the grass. Close the fuel tap approximately two minutes before you finish cutting the grass so that the float chamber is empty. Turn off the ignition.
  9. Clean
    Use the toothbrush and broken china teacup of oil (supplied with the mower) to lubricate the cutting blades.

Below is a list of common faults, their causes and cures:

SympomsPossible causeRemedial action
Fast tickover, low power partially blocked main jet Rebuild the carburettor
Poor starting, runs badly partially blocked main jet Rebuild the carburettor
" partially blocked float valve Rebuild the carburettor
" partially blocked fuel filter Rebuild the carburettor
" dirty spark plug Clean spark plug
" poor seal at spark plug Re-seat spark plug
" accumulation of oil in crankcase Drain crankcase
" poor seal at crankcase drain Re-seat crankcase drain
Does not start too numerous to list Diagnose and rectify
Not interested in lawnmower preservation ? ?

Richard "text flirting with a hot chorister" B


  1. I though this might be of interest to you. It is a section from my old copy of the manual that I am guessing was deleted when it was ammended following magneto failure of the early 2000s. It must even pre-date the kickstart wearing out in the 80s.

    Ignition system testing.
    If you suspect that the ignition system has developed a fault get a gullable companion to hold the sparking plug in free air whilst vigourously operating the kick starter. If the thousands of volts coursing through his body to earth causes him to squeal like a girl and let go of the sparking plug then it can be assumed that the ignition system is operating satisfactorily.

  2. The engine is actually a Villier's F6 as used in pre-war Excelsior motorcycles and Seagull outboard motors. It was obsolete in design before it went into production. It has no good qualities in terms of power, fuel consumption, weight or reliability. The only reason for it's longevity is that it leaks so much oil that it doesn't corrode very fast.

    Doug "fuel filters are a wonderful thing"

  3. Exhaust System

    Should the exhaust system fail. Simply select a suitably sized paint can, drill 5/16" holes in the lid and bottom. Punch a number of 1/4" holes in one end and secure to the exhaust manifold using the supplied bolt salvaged from a childs raliegh bicycle (caution: the thread is stripped so don't torque much more than finger tight)