I managed to get hold of Carbtune II Kit, to help me synchronise the twin 40's on the pinto, to help try and smooth out the roughness.

Whilst doing this I discovered that the 2nd chamber from the front wasn't showing a reading on the tube. It would appear that this chamber isn't drawing the fuel in and unlike the back 2 chambers when I cover the trumpet with my hand nothing happened.

I suspected timing so played around with it for a bit, but it made no difference.

I also notice that there is a puddle of fuel in the carb on the 2nd port, unlike the others where they are relatively dry.

Any ideas?

This is a new set up so now have a good selection of chokes and jets. Is there a setting I have missed?

Thanks in advance!
Rob

What does the carbtune kit show? air flow rates/prssure drop? If so, are you saying that port 2 is drawing no air? or that the carb is flooding down port 2?

Both.

The Carbtune kit (link)shows the air pulled through each port, which allows you to sync both carbs so they are the same. Essentially making sure the butterflys are open the same amount.

There is no draw on the 2nd port and there is a fuel puddle.

This could be 2 different problems, but it seems a coincidence that it is on the same port

So ports 1, 3 +4 show roughly the same, with port 2 at zero? This indicates that for some reason there's probably a blockage somewhere. Does that butterfly open at all? Is there any chance the valve could be sticking? or a gasket blocking the port/leaking massively?

First thing to check would be compressions followed by valve clearances . If it was caused by timing all four cylinders would be affected. Check H.T. leads , distributor cap , rotor and spark plugs then test for inlet manifold leaks .

Great Call...

1, 3 and 4 are all OK, showing the same air flow.

The butterfly definitly moves.

There could be a leak between the manifold and the carb on this port. The rubber spacer is slightly off centre (I had the carbs off the manifold earlier in the week).

I'll have a closer look this evening, and retry running the engine tomorrow.

Cheers
Rob

I had exactly the same symptoms and it was low compression on the duff cylinder caused by valve clearance out of spec. Adjusted clearance and problem solved.

Bottom 2 nuts loose on front carb, but will also look at valve clearance's this evening and retry running the engine tomorrow.

Thanks guys

Sounds like a compression problem to me, either inlet valve not opening at all, or, a major problem with the gasket, or a major problem with the gas tight seal of the spark plug. My favourite would be a problem with the opening (at all ) of the inlet valve, As the others would all give some sort of air flow (however small) through the carb and if the carb wasn't seated properly then it would normally affect both barrels of the same carb.

Hope you get it sorted.

Take off rocker cover & check inlet valve is opening, could be broken rocker or loose adjuster.
HTH
Ian