Date: Fri, 08 Jan 1999 17:20:06 +0000 From: Daniel Price <edpricenopsamntl.com> Subject: Re: Saab 99 popping on over-run
Popping on over-run could be cause by an air leak at the inlet manifold. This cause a weak mixture and poor running. Air leaks at the inlet manifold are more noticeable on over run than when accelerating due to a change in the pressure in the system. To check for a leak, try squirting some WD-40 on the mating surface between the inlet manifold and engine (and any gaskets where the carbs bolt on). Do this when the engine is cold!! Any bubbling of the WD-40 or rapid disappearance of it confirms the problem. chris Baillies wrote: > My '81 saab 99 sometimes pops through the exhaust when decelerating in 3rd > or 2nd gear, is this indicative of a weak mixture/over-advanced timing? It's > had new points, plugs, leads dizzy cap and rotor, mixture set at 3% C.O. > > Other problem is when cold it tends go a bit-lumpy on full choke after 10 > seconds or so, fine on half choke. I know some carbs have a load sensitive > choke (vacuum pull down) but mine doesn't appear to have this. (Zenith 175 > CDSEVX) > > chris