keep a block of 2x6 wood handy to block off the air supply in case of a run away. Dont use a rag!

Brown\blue vac line is for the vacuum fuel shutoff. if its is disconnected the engine should chug right along and idle/run normally. I cant say with 100% certainty if an improperly installed vac shut off valve could cause a run away on a om617. dont think so tho. it is likely caused by something else going one here.

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Current fleet
2006 E320 CDI
1992 300D - 5speed manual swapped

former members
1984 300D "Blues Mobile"

1978 300CD "El Toro"