Barometric compensator (BC) removal quick questions

[Greg R.]

Good morning.

1) What size wrench fits the hex section?  (17mm?)
2) Must a thin tappet-style wrench be used or is there another technique?  My search here last night didn't turn up anything.

-Greg
1967 230SL w/ 250 motor

[jeffc280sl]

The baro requires a 19 mm wrench.  I think youre on the right track for its removal.  Been a long time since I replaced my baro

[wwheeler]

Be on the look out for thin shims under the BC when you take it out. Not sure why you are taking it out, but some use this to do a quickie full range fuel mixture adjustment. You can also test the compensator to make sure it hasn't failed while it is out.  https://www.sl113.org/forums/index.php?topic=12175.msg82217#msg82217

Jeff knows quite a bit about these pumps.

[Shvegel]

I walked out to the garage and slipped the fattest 19mm I had (.35 inches thick) onto the baro of my 1970 and it worked fine.

[Greg R.]

Thanks everyone.

I'll try a couple of 19mm's I have and see what'll squeeze in there.  Thanks for the reminder about the shims.

Yes, I suspect that it has failed or at least want to eliminate it as a variable in my starting & running issues.

[ja17]

When the baro fails, the system usually goes lean.

[Greg R.]

Thanks again, all.

I removed the BC and confirmed that it is kaput. 

-Greg