Check the condition of the idle control valve hoses before twiddling with the mixture. They are probably rock hard by now, and leaking. This will result in no fuel hot (no cold start valve), and hard starts.
The idle control valve is under the air filter housing, about half the size of a coke can. One electrical connection, two 1/2" or so ID rubber hoses.
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!