Morris Minor Owners Club

I'm expecting this may be a stupid question, but I have just replaced my distributor, and the engine is now running much too rich....the spark plugs are completely black, whereas before, they were a 'normal' colour....Is there an explanation for this? Thanks

have you given the car a decent run then taken the plugs out

Hi , yes, the car used to run rich , with very black sooted plugs. I adjusted the mixture with the carb adjusting screw and all seemed well after that, with healthy brown coloured sparks. Since changing the distributor, the car seems to have returned to black plugs, but also it has flooded with fuel a couple of times (Wet Plugs) and been hard to re start. Im just wondering if timing could have affected things, or whether its just a co-incidence that its playing up all of a sudden.

Sounds like something has gone wrong with the carb...flooding over... Check the float chamber...

Will do. Thanks

Maybe the vacuum advance unit diaphragm was holed in the old distributor, causing more air to be sucked into the manifold, causing the engine to run weak. A previous owner then set the carb richer to try to compensate. Now, extra air is not being sucked into the manifold and the jet is set too rich for the current, non broken vacuum advance.

Has the growling noise also gone with the new distributor??

look at this youtube video with a "mechanic" with unfeasibly clean white shirt sleeves. https://www.youtube.com/watch?v=cFfnenMFQ3U a hole in the diapragm in the vacuum advance would mean more air getting into the inlet manifold, hence weaker mixture and also no vacuum advance so under load the engine would sound like the timing was retarded. Along with the extra air being sucked into your manifold, hence the growl...

Yes - ^^^^^ very good point!