Vintage Cars: 67 Austin Healey sprite poor perfromance, austin healey sprite, deg btdc

Question
I have tried everything. Rebuilt carbs and new parts and like crazy. The motor runs fine at idle and accelerates downhill or flat ok but uphill and under load terrible. RPM at idle is high and doesnt settle down.
Carb balance good, no leaks noted, compression great, new fuel pump.
Help

Answer
Sounds a bit like my big Healey, right now! Suspect the distributor/timing; and it sounds like too much advance at present. Of course check the points (new ones are best) and gap. 1) Waggle the main shaft (the rotor) to check if there's too much side-to-side free play in the shaft; if so a rebuild might be necessary. If too much play the rotor can't deliver the spark to the wires. 2) Check the little flexible wire that connects the breaker plate to the body (they go bad quite commonly; replace with braided wire only, not solid: it has to flex). 3) New condenser (capacitor) might be good. 4)And of course check the timing and mechanical advance. A timing light (get one with the knob for measuring advance) is essential. I don't know the timing for the Sprite; probably 12-15 deg BTDC at 600 rpm or similar. Important too, check the advance: it should go slowly up from about 1500 to 4000 rpm (crankshaft) to a max around 30 deg (again I don't know the actual specs). If it doesn't, or if it advances too much at low rpm, another indication for rebuild: rollers and springs. I don't know where you are but if in the US, Advanced Distributors in Minnesota are good and not expensive (www.advanceddistributors.com).

If it's the carbs, a quick check on the mixture can be had by pulling out the choke a bit when it falters unde load: if that instantly cures the problem, you are much too lean. The color of your plugs will also tell you: a brown electrode is good; flaky white/beige is too lean, and sooty is too rich.

Hope that gives you some hints.

Jo