Author Topic: How can I tell if I have destroyed my pump or just messed the settings?  (Read 3401 times)


  • Guest
Hi guys and girls.

New to the field of Mercedes Mechanicals, I usually work  on Race Rotarys.

But have purchased a near perfect W108 1968 280SE 6cyl, it has been off the road since 1994 @98,000 kms on the clock, the issue with the car was the old guy who owned it couldnt drive so parked it in 1994, a year later he decided to try and turn it over, to cut a long story short he tried using the Cam bolt to turn it over snapped the bolt and decided it must be siezed so micro dismantled the engine.
Fast forward 20 years later I have bought the car, I will rebuild the original motor over time, but to get it usable have purchased a complete spare car to use the engine out of it, the spare car was very very rusty but the mechanical s are very good, it is a 1971 so a couple of differences, but fitted no problems, got it running all nice until!!!

Went out to start it Saturday and it was very hard to start and was missing badly, to only thing I had done the night before was to fix the exhaust, rusty with holes half way down, and connect up the brake booster assist pipe and block off the vaccum hose that runs the central locking on the 1971 vehicle.

it would run but was rough, thinking it might be rich and reading that there was an adjustment screw on the pump I went to adjust, yes I can hear you all shouting dont!!, we I did, the adjusting screw spun anti clock wise and that was it, it was running way rich.
So my issue is, I have fitted the pump off the original motor, it was sealed up and Kms are known, I wound the motor to 20 deg after TDC, pulled out the pump, checked the markings to make sure that both pumps were timed exactly the same, fitted the pump, but the car fires starts then stalls.

So after that long story is anyone able to assist?

Do I
Persist with the 1968 pump, and check timing, as I have read that it is possible to get it 180 out, but given the fact that both pumps were lined up identical I can see how.

or can I save the other pump that was working, I have taken the cover off the adjusting know, the adjuster is no damaged and I was able to easily wind the adjusting bolt back out with know effort.

Your assistance is greatly appreciated


  • Guest
Re: How can I tell if I have destroyed my pump or just messed the settings?
« Reply #1 on: September 01, 2015, 00:11:20 »

i spoke with a mate who rebuilds diesel pumps for a living, one of the guys he works with used to work on these pumps 15-20 years ago, he gave me some very useful tips, I adjusted the pump and Bingo it is running, still need to do some linkage adjustments and eliminate a miss fire it has, but it is running sweet no smoke, revs and doesn't stall.....yay