BTW - while you are playing with vacuum lines try putting some vacuum on the secondary throttle diaphragm to make sure that works - it's a common failure on the Mikuni's resulting in lack of power.

dan

1986 Montero 2.6l
31X10.5 BFG MT - Weber carb with custom intake
Rear LSD - RCI seats - Oil cooler - Manual hubs
Custom bumpers front and rear + rock sliders