Weber problem: suggestions/ solutions welcome

[Caprimaniac]

Hi, all.

No; no problems with the V8 this time, but it's related in some ways.

The most brutal UK/ European ford- engine during the 70's was the 3- litre V6. I have one topped off not with IDA's or IDF's, but because of restricted space, the WEBER DCNF or Dino carbs as they are named after the Ferrari Dino V6. It was also used on some italian V12's and also V10's if I remember correctly.

So, this is an IR- setup, just as on my 347 and as on your 289/302/331/347/351/308/327/390/428/429/460 etc.

Problem: When idle adjusted; screws out 1/4 turn (large jets), flow adjusted, 700 rpm and 10 deg advance, the engine runs smooth & nice. But when the throttle is used the engine won't come back to normal idle. It will stay at 1200 rpm and maybe fall back to normal in , say, 2 minutes time. There are also very strong popping noice in the exhaust at this time; not dull but rather hard and very strong sound.

Had same problem even with smaller idle jets and with large jets and screws turned more out.

Other symptoms: at idle there are some poppping from the carburettors.

The holes for the idle jets were cleaned out with compressed air. (But not the idle volume setting screw holes.)

I do not suspect clogged idle ducts/ too lean idle, since popping never comes on when the engine is left alone (throttle not used).

My only suggestion is a leaking inlet manifold gasket. Is there a test, other than spraying fuel or starting gas around the manifold to check this?

Suggestions is more than welcome!