Thread: Zenith again!

I have been having issues with my carburettor for years (even after replacing it with a new one).

Yesterday I removed it, and took the top off and replaced the O-ring. I was disgusted to find that no, this did not fix the rich and unadjustable idling mixture.

So this morning I pulled it off and pulled it apart again. This time I removed the emulsion block to replace the gasket as well, although it looked perfectly OK. And found, in doing so, two potential issues.

The "ventilation jet", whatever that does was loose and had unscrewed right up to the top of its hole. I have no idea what effect this would have had. And when screwing the needle valve seat back in, I spotted something inside it. Fishing it out, it seemed to be a bit of wood, about 3mm long and 0,5mm across. I wonder if this had intermittently been getting between the valve and seat?

Putting everything back together, being especially careful with seating the O-ring, it now seems to be working properly, and I am now able to adjust the idling mixture successfully. (This is actually an air bleed adjustment.)

Originally Posted by DieselLSE

Refacing is the important bit as they tend to warp and no amount of gaskets or tightening will work.

I had the warp issue with the carb on my Hillman Super Minx. I needed to pull the choke on when stopped or it would stall. My son (when he owned it just before I inherited it) had the carb serviced by a carby place but it made no difference.

I pulled it down, lapped the top on a sheet of wet & dry laid on a pane of glass. That fixed it.