I have rebuilt completely series 3 engine. Put back together and it runs. Have stripped and rebuilt carb twice, replaced main jet, secondary pump jet, set float chamber to less than 30 mil, have replaced venturi O ring seal twice, all to no avail. Zenith etc cannot answer the problem. It still runs too rich and is hunting and stutters on acceleration, plugs black up within 10 mins. Any ideas? Just to confirm it is a 2.25 petrol.

 

Nice link for ya; http://www.series123.com/AUShomepage...137/index.html

Best of luck with a tough carb to make work right even when new.......

 

Thank you. Yes, I had found this link and the only thing left to try is to look AGAIN at the diaphragm in the top section to see if sedimented up . But checked on previous occasions and looked all ok. if not then a gun is probably in order!

 

Just re-stripped and cleaned out diaphragm as suggested by post . Slightly better but still too rich. have just ordered a fuel pressure regulator valve from Zenith. This apparently according to their manual can often be the problem if all else is checked and cleared.
I will let you know how I get on.