Weber Carb GU Engine K&N Aftermarket Issue

Okay so this is the engine setup;
Originaly a GU 1.6,
Engine swapped out for a GU 1.8 running a Webber carb and K&N induction kit, manual choke.

The issues are the following
- After driving for 5-10mins it will then struggle to start again, but if just left on idle for any amount of time without driving it will start straight up without the choke.
- On a run it seems as though it is under fueling it's self and I have to drive with the choke out else it judders a lot (naturally MPG suffers along with performance)
- It is getting a lot worse with the sudden cold nights and making driving anywhere on a night an issue.
- I drove around the other night with the heaters on full whack the entire time after letting it warm up before driving and it was okay on a 8 mile drive. Even pulled in for a minute and it started straight up.

I decided to rebuild it all yesterday as I've only just recently got the car and found no major issues but decided that I would replace the flange plate as it has some rough perishing around the edges and in the center, still the same issue.

The heat sensor that sits in front of the carb and is screwed on was also damaged so I've replaced that with a new unit as well.

People have been saying that they think it's carb icing but it done it yesterday within about 800 meters of leaving my friends house.

Any advice would be appreciated.

Thanks,

 

I guess you mean the 'on top of the carb' style K&N, not the panel filter in the factory airbox?

If so, the carb heater is much more critical to avoid icing, so check that you have 12V at the feed wire to this heater when ignition is on, and that you can actually feel the tip of the heater getting hot.

You have got an earth/ground brown wire going from the carb to the rocker cover, right?
Carb heater won't work without that.

I'm not sure that your idle jet isn't sucking up a bit of debris from the float bowl, but presumably you cleaned everything out nicely when you refurbed it?

 

Everyone is saying bin the K&N pie dish style inlet.

Going to source the original parts

 

My webber seems to be suffering abit in the cold damp mornings now.
Will need to source a flexi pipe from manifold to warm are intake pipe.