Thread: HELP: Throttle mechanism

Was driving my LWT today (110km on the clock since full rebuild) when engine started racing. Pulled over but for some reason car no longer idles but goes to high revs without touching accelerator. The mechanism looks the same as it did before but it doesn't return to idle as a default. Everything seems to be in place but got home by adding another spring to throttle arm on carby (to chassis) to hold it at idle. Accelarator peddle now sits very high.

Any suggestions would be appreciated. Thanks.

First of all, I'm not familiar with the lightweight, but I'm assuming it would have the same or near enough the same system of linkages, I would be looking very closely at the torsion spring that holds the carby bell crank lever.
This is (on Series L/R's) is bolted to the bulkhead/chassis support panel LHS of engine bay, it could be just that the nut on the back has come loose or the spring is broken, anyway I hope thas of some help to you, cheers Dennis
here is an exploded view of the bell crank item