Small vacuum hose to cam cover breather

[Brett C]

Good afternoon all,

My '73 Spider 2000 has a small nipple on the inlet manifold adjacent No 1 inlet which is plumbed to the breather on the cam cover. Web searches suggest that this seems to be correct, but can anyone tell me what purpose it is intended to serve?

All I have been able to determine is that this seems to be causing No 1 cylinder to run lean and misfire at idle, and make the no 1 idle mixture needle just about completely ineffective!

Regards

Brett

[Brett C]

Update

I capped both ports and hooked up the manometer. An imbalance that previously existed between #1 & #2 was gone and I was also able to fine tune the balance between the two carburettors. The idle mixture for #1 was now behaving itself, a persistent miss at idle in #1 was gone and the engine was idling happily. Now I'm looking forward to actually driving it!

I'm still at a loss to understand what purpose the vacuum port to breather was intended was intended to achieve....?