Oxford Allen no power

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This topic contains 10 replies, has 6 voices, and was last updated by  martyn-c 2 months ago.

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  • #28847

    martyn-c
    Participant

    I have an Oxford Allen serial number 95671 with 2-stroke Villiers motor. It starts and runs reasonably well but will not rev and cuts out when asked to do any work. Can anyone give me some advice on how to sort this problem? Many thanks

    #28848

    ted20
    Participant

    could be coil giving warning of giving up, does it cut out suddenly or stutter ? if stutter I would look at carb. Villiers electrics sometimes give good spark until put to work then there is no resistance hence engine cuts out try simple things first like spark plug, condenser etc.

    #28855

    rollomk6
    Participant

    Hi martyn -c also check your ignition timing as it is very important with a two stroke

    #29100

    martyn-c
    Participant

    quick update
    have carried out timing check again and again pretty sure its good. have cleaned carb til it shines 🙂 but still no improvement. plug is new. latest thing i have noticed that after around 2/3 throttle it actually gets worse, which leads me to think fuel shortage. is fuel getting into bowl quick enough? wrong needle? wrong float?or what size should main jet be? as you can see clutching at straws now.
    any help or thoughts appreciated or anyone with working carb near derby?

    #29101

    andyfrost
    Participant

    “IF” you,re absolutely certain the timing is correct , as it has been mentioned previously , it is vital on Villiers twostrokes.
    You have now got to investigate both the crankshaft seals , and cylinder bore/piston rings , unless it’s a very late 25c , the crank seals will be the gland bush type.

    Andy.

    #29107

    merry-tiller
    Participant

    Gradual flywheel slippage affects (retards) the timing and although it may have been perfectly assembled to start with it can end up too retarded to do any real work. I used degreaser, flour paper on the shaft to dull the finish then some Loctite. It lasts about a year before I have to redo it! Why Allen didn’t key the shaft at the correct timing only they will ever know!

    #29108

    charlie
    Keymaster

    The secret to stopping flywheel slip is degrease and clean both parts of taper then tighten flywheel properly. Villiers supplied a special ring spanner for this with a large lump on the end so it could be hit with a hammer.

    #29110

    martyn-c
    Participant

    thanks all
    have snowpeaked the timing marks to make it easier to check and all still seems to be good, degreased taper every time. andy are you thinking it may not be ‘sucking’ enough? this would surprise me as put hand over carb when running and it ‘sucks’ 🙂 . still puzzled why it would get worse when throttle goes above 2/3, makes me think too much air not enough fuel, does anyone agree? still open to any or all suggestions. will defiantly get this sorted. hopefully!!!

    #29118

    charlie
    Keymaster

    I never use the timing marks on Villiers engines. I always set timing by setting piston at correct position eg 1/8″ BTDC for a MK15, then set flywheel so points are just opening. Checking several times during tightening of flywheel to make sure it has not moved.

    #29122

    andyfrost
    Participant

    That’s VERY sound advice from Charlie , I too , never rely on timing marks , machines of our era have more than likely had various parts swapped during their working life , none more so than Villiers ignition plates.
    Your 25c may appear to have ample “suction” , but is your crankcase compression being lost through the main seals.

    Andy.

    #29126

    martyn-c
    Participant

    thanks for the advice
    looks like a happy weekend doing timing and compression test. keep your fingers crossed 🙂

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