While driving the revs would suddenly drop and then catch up again after 3-4 seconds. Over a week later the revs would drop down to 500 as if the fuel was starved. Another week later I could not do over 30 miles per hour and broke down on the motorway. Called out emergency rescue who suggested to disconnect the hose from the Hot Start Valve to the Carb plastic cover. This worked almost fine for a few weeks but the problem returned.

On advice from this forum I cleaned the crankcase vent hose, replaced the flame retard, renewed all cracked carb hoses, new fuel filter, new mechanical fuel pump (mechanical). Then I made a mistake of letting an amateur loose on my car. He adjusted the idle speed which is at the back of the carb and the idle speed mixture which is at the front of the carb. Now the car won't even start and when it does for a few seconds the carb pops.

Question 1. In order to get the car to a local garage crudely how far in should the idle screw and the idle mixtrure screw be in/out.

Question 2. Any tips on the original problem. My car is a 1987 740GL saloon manual with 2B5 carb and done 170K miles and has been lovingly cared for. I live in London and Volvo want to charge me $200 per hour to diagnose fault alone which they say could take up to 2 days.