Follow-up: backfire on over-run

[Jeff Boatright <jboatri@emory.edu>]

Car: 1965 spridget with 1967 1275 cc engine, dual SU HS2 carbs.

Original sympton: Installed a rebuilt set of carbs and got a lot of
backfire out of the tailpipe on over-run (i.e., take foot off accelerator
pedal and let engine slow car). Did not happen with old carbs, suggesting
that this is not a problem with the exhaust system.

Partial solution: Set the carbs slightly rich (about 1-1.5 flats rich using
the piston-raising test). Backfire is lessened but still present. Going
richer is just too rich once air cleaners are installed.

Any other suggestions? (Different needles, etc).

Thanks for all of the input on this.

Jeff

Jeff Boatright    __o_\__           '65 Austin-Healey Sprite
http://userwww.service.emory.edu/~jboatri/sprite/sprite.html