16 replies to this topic

[alpder]

Trying to think of anything else that could make the idle erratic other than fuelling/air leaks - one thing that occured was something loose/worn/broken in the distributor allowing the timing to wander at idle.  What distributor are you using and where did it come from?

 

Distributor is the original Metro electronic with vac. 65DM4. With a basic timing light it shows steady as a rock at all rpms, and advances smoothly. Even so, I might send it off to Distributor Doctor for a check-over, just in case, if nothing else solves these problems - especially the sudden cutting-out.

[alpder]

If the float is set too low like the picture the fuel level will also be low and it won't run as it's designed to do. 

 

With all the issues present in this carb there's plenty of things that will cause poor running

I've reset the float level and still I can't get it to idle nicely. The remaining carb issues (bad seals on the spindle, needle now probably over-rich at cruise) don't seem enough to make it impossible to get a good idle setting. But maybe spindle air-leaks matter more than I think they do. There is, after all, a "good" clearance at the bushes: 0.2mm slop in all directions which means 0.1mm gap all around the spindle, both sides. And those spindle-seals were doing nothing because they were fitted back-to-front.

 

Today's job is whip the manifold off and check it's airtight. But I'll be amazed if it isn't.

 

Edit: I've also tried blocking the CCV pipe, makes no difference to the idle. But just in case, there's been a new oil-filler cap on the engine and a new O-ring on the dip-stick since a thousand miles ago, too. You can feel the suction as the CCV pulls the filler-cap onto the engine. So leaks in that department aren't it, either.

Edited by alpder, 23 March 2025 - 09:52 AM.