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Thread: TR4 Carburetors/Idling

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    TR4 Carburetors/Idling

    Have adjusted the carburetors SU-H6 as the two front spark plugs were running too rich.
    Flow meters show identical measurements. Gunsun Colortune shows blue/ red flame.
    Still the two front cylinders are fouling the spark plugs. If the mixture is set to more lean, it won't idle when driving f.inst. when reaching a crossroads.
    The idle is set at about 1000 rpm, but still stops if mixture is set to more lean .
    Engine runs perfectly and has plenty of traction
    Carburetors seems to be in quite good condition
    No vacuum leaks
    Any ideas ??

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    Re: TR4 Carburetors/Idling

    1. Whenyou say "fouling the spark plugs," how are they fouled? With carbon or oil? If it's oil, it has nothing to do with the car setup or timing.

    2. If it is indeed carbon fouling, it is running rich. If you can't make it work with a leaner mixture, something else is wrong. I'd start with the basics: set the valve lash, then the timing, then do the carbs in the traditional method, not with the colortune. I suspect that will work.
    Steve Maas
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    Re: TR4 Carburetors/Idling

    Quote Originally Posted by TriumphTR4_DK View Post
    Have adjusted the carburetors SU-H6 as the two front spark plugs were running too rich.
    Flow meters show identical measurements. Gunsun Colortune shows blue/ red flame.
    Still the two front cylinders are fouling the spark plugs. If the mixture is set to more lean, it won't idle when driving f.inst. when reaching a crossroads.
    The idle is set at about 1000 rpm, but still stops if mixture is set to more lean .
    Engine runs perfectly and has plenty of traction
    Carburetors seems to be in quite good condition
    No vacuum leaks
    Any ideas ??
    I think the very first thing to check before adjusting jets is to verify the correct float level by visibly checking the height in the jet. After some cranking with engine off it should be just below top of jet.
    Tom

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    Re: TR4 Carburetors/Idling

    Try a hotter plug.

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