Series 2a Carbie problem - fixed

[JDNSW]

Thought I'd post this in case it helps anyone.

A couple of days ago the 2a started refusing to idle without the choke pulled out a bit.

So yesterday I pulled the carburetter (Zenith) to bits to clean, and found no problems. Still no better. So this morning I pulled the PCV valve to bits, expecting to find a perforated diaphragm (it wasn't), and also checked the vacuum line was not leaking or the points closed up (neither was a problem).

After thinking about it, before lunch today I pulled the carburetter to bits again, checked in the book which is the slow running jet, and had a close look at it with a magnifying glass. Once I had dried it of petrol, it became clear that it was blocked by something transparent and hard, possibly a grain of sand. It would not dislodge with compressed air, but eventually, working under the hand lens, I was able to dislodge it with a needle without damaging the jet.

Reassembled it and now ticks over like a sewing machine only quieter. The idling mixture needed to be weakened a bit, suggesting that the jet had been partly blocked for some time.

I have no idea how it got there, as the fuel line has a filter on it. Best guess is that it came off my hand last time I had it apart, which was to lap flat the top cover a few months ago, and swished round in the bowl until it was sucked into the jet.

John

[JohnE]

Interesting point, JD, I think fluff and the like was discussed , in a post not too long ago, the one from the bloke( can;t remember the name) who wanted to know if a particular gasket fitted on his carby.

Anyway I think I related a prob i had many years ago with the carby in my FE, same symptoms you described when i pulled it to bits i found a piece of fluff blocking the jet.
Makes you wonder sometimes, whether we infact introduce foreign matter to hard to spot places when we work on cars,

Your example makes all the sense in the world to have a decent magnifying glass in the tool box.

BTW if you haven;t had any yet am sorry but its pouring up here, the pool is getting to the , pump some water out stage.


john

[JDNSW]

Thanks for the thought!

There was a brief shower this morning - but not enough for the pock marks in the dust to touch. Nothing else, and it doesn't even look like imminent rain, although it has been overcast most of the day. But judging by the TV reception there is something between here and the transmitter about 100km away. And rain is forecast for the next three days - but then it was for today as well.

John

[JohnE]

Well mate
my drain frogs have been singing a merry tune for a week now, plus they are all sitting in the carport now, the rain drove them from the gutters.
from what I saw on the news tonight there is a bit front coming across the centre of NSW,
so I hope it slowly soaks your end of the world, I think about 15mm a day for about a week should be a good start
we are a bit too green here at the moment, have to mow every 4 days, plus the ground is saturated and the tanks overflowing.


john