I have a (very) old Suffolk Punch, with the engine that uses a Zenith carburettor. It was running very well. Then, suddenly, it stalled on me and wouldn't restart.

I cleaned & regapped the spark plug, checked the carburettor float, etc. It would start and run for a few seconds (but at low power, however much throttle I used), then stop.

Today, I fitted a new spark plug, new float & new float chamber gasket. I checked the ignition points.

The beast started beautifully and ran at full power for a minute or so. I stopped it, because I wanted to adjust the clutch take-up. When I restarted it, it was running at low power for about 30 seconds, then stalled (ie, back to square one). I suspect the carburettor may be flooding, but not sure.

Any ideas?

John W, July 2009

try blowing thru the carburettor sometimes the little jets get blocked an airline is prefered for this job but a bycicle pump should do the trick
then just to be sure clean out the whole thing with carb cleaner you can get this from halford or other motor shops some garages even sell it

edd, September 2009

adjust the needles

Ross, August 2009

I have experienced the same problems. Beyond what you have already done, when carb float chamber is dissassembled, remove the petrol feed tube and ensure it is clean through. you may need a very fine strand of wire. Partial blockage will cause low power, full will starve fuel to point of stall. Failing that, locate the other jet behind blank screws and clean it. On full assemly ensure the float chamber is clean and free on 'bits'!. Should now run ok unless flooding was the problem (was plug wet with petrol when removed?

Steve J H, August 2009

Firstly, if the petrol leaks out the floatchamber after you have cleaned out, then the float is not doing it's job.If not leaking you have reassembled correctly.
The problem is your Ignition Points. You need to remove the engine cover,then the flywheel to expose them. Remove carefully mind you don't break clip.Emery the faces of each and reassemble.set gap to 25thou. Then rotating the crank make sure they open/close.Rebuild and check for spark.

David, July 2009