Quote:
Originally Posted by boatmartinm
Mercedes OM615 with a pneumatic governor. Starting up from cold it's about 450 rpm then over about 10 minutes it climes to just over a thousand as the engine warms up and there it stays. I have tried disconnecting all the linkages and the adjusting screw is wound right out. Nothing i've tried brings the revs down. Im thinking its something to do with the governor but I don't want to mess around with it without knowing what i'm doing.
Martin
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Inside the regulator there is a membrane which on this forum is often referred to as the "pig's bladder" - when this breaks / has a hole in it you get the symptoms you describe.
Check the plumbing between the regulator (back of the injector pump) and the throttle valve at the air intake before you start looking at the regulator.
To test the system you can use one of those expensive Mity Vacs or the alternative boxed in red plastic offerings from the bay of ee to see if it holds any vacuum.
To the best of my knowledge the spare parts are most likely to be found at the dealership rather than other place
If I remember rightly 450rpm is a bit on the low side but I wouldn't adjust anything until you get this revving higher when warm problem fixed