Weber 32 DRT 8 carb sticks on full throttle

[Pickup]

Hi folks,

Looking for some help / advice on a Weber DRT 32 carb. Vehicle is a 1985 Renault 5 Automatic (1397cc) with 32,500 miles had been laid up for 15 or so years but in use for the last 2 months (1500 miles).

Intermittent fault which occurs if full throttle is applied (ie accelerator pedal is fully depressed) for example when overtaking (which doesn't happen very often), pulling away at a roundabout or going up a steep hill. Engine "races" - revs don't drop when throttle is released (no rev counter but I'd estimate 4500-5500 revs). If neutral is selected and foot removed from accelerator pedal then (usually*) after 2-3 seconds the revs drop to normal idle speed.

Problem occurs more frequently when engine is at normal operating temperature.

• Sometimes the ignition needs to switched off (vehicle stopped at side of road/ car park) for 3-5 minutes.

The Haynes manual for the car refers to "additional enrichment provided by a pneumatic device" under high load or acceleration which opens a "valve" to allow additional fuel in to enrich the mixture. I suspect this valve or the "pneumatic device" is sticking but so far am unable to source any significant documentation on the carb - the Haynes manual does give some info on basic setup (float level, fast idle).

Have given the carb a blast of CarbCleaner with no appreciable difference.

Thanks

[GreenV8S]

There was one R5 with a manual choke that had the choke spring fail. Didn't normally cause any problems, but if the throttle was held wide open for long enough with the engine running then the choke could rattle around far enough to engage the fast idle cam. This was a turbo which produced enough boost to keep the turbo spooled up at that throttle setting, so it was quite exciting when it happened. Don't know whether it's applicable to that carb, but worth checking whether the throttle is mechanically fully closing when the problem happens in case it's something similar.