Hi All, I am taking my two young sons camping tomorrow and as the weather is favourable I thought I'd take my 1975 Series III SWB. So today I did the usual checks before the 1.5 drive to the new Forest. I had been meaning to tighten up the top of the exhaust to the bottom of the exhaust manifold as its been farting and popping for months. So after administering a bit of WD40 I succesfully tightend it up and now there is no play or blow from the joint. Pleased with this i fired her up to see if the farting and popping had stopped - it has. However it now wont idle and on going for a run the engine cuts out when not on the gas or when slowing for a junction etc. What have I done!? it idle'd beautifully before. (It did do this back in the spring which I remedied by removing the large bore air hose from the top of the Carb and dribbling in some neat RedEx that solved the problem) Any words of wisdom before I tinker more and make matters worse?

I can't help with your question but worth reposting this in the Series section.

Blocked exhaust? Maybe a partial blockage that the exhaust pressure manages to blow through at higher revs?