Lotus Esprit S3 ride along - running rough?

[@edwinblank58]

Carburetor throttle shaft play can be the cause due to false air.

[@SportsandGT]

Yeah I think I may refurb/service the carbs over the winter.

[@Eddieboote]

Check the spark plugs first, to focus on which carb. What kind of fuel you using? Premium or Supermarkt stuff and stay clear of E10. Has the car been laid up? Could be vanishing of the fuel in the jets. Is it heat related? Does it do this only when hot? Might be ignition related? HT leads or coil. Can be so many things. You have run through and tick off. Exhaust sounds like it’s leaking- re fuzzy sound at some point, but might be wind noise or your mic.

[@SportsandGT]

Thanks, yes all things I’m looking into. Plugs, leads, coil, lumenition etc have all be replaced earlier this year. Not just when hot but that seems to make it worse. Some of the noise is down to the mic, wind and road noise but it isn’t in the best of health carb-wise. Synch keeps unsynching!

[@neildonaldsonlotusexcelresto]

It does 'pop' quite a lot Stuart... Possibly running slightly rich?

[@SportsandGT]

Yes - I think it's the carb balance maybe. They're balanced and after a while they revert to one carb doing all the work and so it gets lumpy at low revs and unburnt fuel gets through. Wondering if the synch adjustment screw works loose.

[@garychapman7495]

Not got a cast iron manifold with crack by any chance

[@SportsandGT]

I don’t believe so. A lot of the fluffy sound picked up was wind or road noise.