v8 Carb Disco - very high idle... all of a sudden

[thepsychoman]

Okay, got a problem with the Mrs' V8 Disco. Its an early 1990 model, 3.5 with carbs.

Basically its been running fine, up until today. On the way home my wife noticed that the idle speed had crept up - to the point where its sitting at around 2000 rpm. I've checked the throttle linkages, choke cable and dashpots, but can't find anything jammed or sticking... and its still sitting around 2000, pretty constant. It seems to run okay otherwise, pulls okay and theres no smoke... so - any ideas?

Thanks

Dave S

[beast5680]

it may be the little poppet valve in the carb butterfly stuck open it may just want cleaning or it may be u/s

[Skibum346]

it may be the little poppet valve in the carb butterfly stuck open it may just want cleaning or it may be u/s

Bossman of my local 4x4 specialist pointed this out the other day... warned me to check it as backfires from the engine fry the spring on this valve as it sits engine side. This makes it brittle or soft... poppet valve then allows air in when it shouldn't.

His solution was to solder it shut.

Skibum

[beast5680]

couple of people i know have soldered theirs shut and had no probs since mine are ok at the minute so i havent bothered

[thepsychoman]

Thanks guys - good call on the poppet valves. Sealed 'em shut and problem solved. Thanks for the advice.  8)

[beast5680]

excellent glad you solved it and cheaply :D