Andy:

Most likely you pulled a vac line off while changing the fuel line.

The brown plastic line is the supply, the brown line with a blue stripe connects to the vac servo on the IP to shut the engine off.

Use the stop lever to kill the engine until you get it fixed.

There is also the possiblity that the servo died, you are about the right milage.

Use a MitiVac hand pump to test -- engine should stop instantly when you apply vac to the servo with the hand pump. If it doesn't, or the vac leaks down, replace servo.

Peter

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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!