As the mornings are getting colder I've started having to use the choke on my old Volvo 340 1.4. The problem is that whenever I open the throttle, a warbling/whistling sound comes from under the bonnet and the revs drop right down. This only happens when the choke is out. I
*think* the sound's coming from the carburettor but can't be sure. Any suggestions as to what's causing this? I've checked the following: All pipes on carb/air filter are secure Carb isn't loose (!!) but shows signs of small amounts of fluid leaking.
Would a new air filter make a difference?
All help appreciated. Mike.