Petter A1 Zenith Carb setup

Our Petter A1 is a bit of a pig to start and is a bit 'lumpy' when running. We have a big fat spark and loads of compression so we are guessing that it's an issue with the mixture. It has a Zenith 24 T2 carburetter. Can anyone give us a reasonable starting point for setting the adjustable jet and the air regulating screw?

Hi Paul,

My A1 was a problem much the same as yours until I found this you tube ref< I know its for a lister d but principle the same,
https://www.youtube.com/watch?v=GgiIXWmhz2Q as for the jets, mixture on mine is about 2 1/2 turns out from stop then just played until ok, the air regulator screw is about 3/4 turn out from stop, I checked the magneto and it was out by nearly half a turn and now starts first time and runs a treat, hope this helps, Regards Richard

Hi Richard,
Pretty sure timing is OK - Impulse clicks when keyway is at 6 o'clock.
Will try your settings for mixture and see how we go. Cheers.

Hi Paul,

You need to look at video, as its not the engine timing I am referring too its the magneto timing, which is different all together.
I would try and explain but not good at that, just look at video and all will be revealed.

Hi Richard.
Had a look at the video then whipped the top off the magneto.  Unfortunately ours is a type A so the internals are a bit different.
The only adjustment available is to slacken off the bolts and rotate the whole thing. But we did strip down the carb again and give everything a good clean. Reassembled and filled the sediment bowl with fuel and she started much more easily and ran better. So we are pretty much convinced to go down the fuel/mixture route.
Will post video later.