Right so Hetty doesn't have a fuel filter...

I've changed the plugs.

Hand (or thankfully) block of wood over carb resulted in even crappier running and a flame shooting out the too of the carb.

So what am I looking at here, blocked jets?

Whip the carb off and find out

Sam,you should be ashamed of yourself

OK, so firstly I tried the hand over top (used a block of wood) until the engine died, then took it off. This actually made things worse

So whilst I was at it I changed the plugs. The old plugs looked like this:



The one on the left I thought looked decidedly ropey.

Change of plugs didn't help either really.

So I took the top of the carb and found quite a bit of sediment in the float chamber. I emptied the float chamber and cleaned out all the sediment. I also blew through the jets and took off anything that would come off with holes in and blew all that through too using my home made 'air compressor' (lungs + modified drinking straw).

I cleaned everything up and also cleaned the fuel filter that's built into the carb at the front.

I also discovered that Hetty doesn't seem to have an in line fuel filter HOW HAVE I NOT NOTICED THIS???


I also took the cover off the points box - there was a little oil - and cleaned that out.

With everything back together she seems to be running better.

I walked down to the nearest petrol station and got a gallon of fuel which I've put in the tank. I'll leave that to settle while I eat some nosh and then take her for a spin and see how she does.

Nope still ducked. In fact, it's worse, much worse than before. And it's not backfiring it's popping (burping?) up the carb and into the air filter

Tick over still fine though.

No power beyond tickover unless I rev the nuts off her but she still pops and misfires

Weirdly, it feels a lot like the time I had diesel in the D*lly...

Did you take all the jets out..? Incl the main one..? Sounds to me very much like blocked jet. And the fact youve disturbed the sediment and its worse says jet. I assume you cleaned put the sediment before the jets

From the jets in carbs ive played with before you can normally tell by looking inside if its badly blocked,

my brothers ak van had a similar prob a few weeks back sam
turned out to be the accelerator pump jet blocked at the tip,the part comes out easily once the carb top is removed
i blasted the part through with my airline from the tip back(not the other way)
then blew through it to check it was clear
put it back-- all good
xx

Have you checked the timing?

samfieldhouse,
actually there is an inline fuel filter incorporated in to the Solex 28 and 32 and 34 and 26/35 carburettors.
Item 1.

If it were a problem with the accelerator pump, it should only cause a problem as you open the throttle. After a few seconds at any given throttle opening it should be fine. Is the fuel level in the float chamber OK? You could try stopping the engine whilst it's giving trouble, and then having a look?