Well Team,

After checking and adjusting everything within my competetence, I have concluded that these carbs have problems beyond my capabilities and time.

Trying to get an idle, I pulled both fuel blocks, checked for obstructions, verified fuel level, blew out idle circuit, surfaced the covers (they were slightly warped) and put them back together being sure the gaskets were right and no holes were blocked.

Result was no change - still runs a bit rough and will not run below 1000 RPM. The kicker, though, is that it will only do this with a shop rag folded double thickness and laid across the rear barrels. Take the rag off and it really goes to crap, missing and backfiring. The front is dumping gas out the pre-atomizer, which means no idle circuit.

My conclusion is that I probably have warped fuel block and base surfaces resulting in vacuum loss, in different areas, of both carbs.

So, I'm out of tricks. But the old guy is running well enough to demonstrate starting, oil pressure, and no noises.

Christy and Mark V - I wish you better luck.

Chuck

Well Chuck, you're not exactly inspiring confidence.
I'm sorry nothing comes to mind to help short of throwing a ton of bucks at it.

WE'VE got the same problems!!!!!!!!! I can feel your pain....BUT this is NO TIME to give up.

There IS something wrong with your carbs...but crying about it isn't going to help. Although, shouting obscenities helps....AND is highly recommended...

C'mon Chuck! Don't kick your carbs to the curb! Think of all the quality time you've shared with those carbs...

As YOU put it, getting some "new" carbs will only put you another step behind.

So your carbs like to hold a "blankie"....it's ok..We all need something to hold onto sometimes....

Maybe your nozzle overspray is cause by somebody poking it with a wire ....the good news is that your pump works....get a new nozzle..it pulls right out.

It's all in the adjustments...that's what they say...

Keep on keeping on..

~Christy

You have to pull the whole carb and soak it. The last timie I did it, the local shop charged me 75$/carb if I gave them the fully disassembled unit and got back a pile of parts that were shiny clean and all the pot metal parts chromated.

Perhaps it's something as simple as the carb isn't bolted down well to the mainfold or there is a leak there.

-CTH

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http://www.111lakeside.com/

You guys are right.

But I need to explain my reasoning a bit more.

Remember that this all started with the 250C's trans not working.

My decision goes back to the whole purpose of the 280S, which was a freebie (thanks again to DrDKW for the lead). I wanted to get the engine running to verify that it had compression, oil pressure and was in fact in decent condition. Even with the carbs the way they are, I verified that the rest of the engine is sound.

This is important because now I can drop the engine, clutch, and trans into the 250C as a unit. This saves me a ton of work - unbolting the clutch/trans, and flywheel, rebalancing the flywheel, etc. I will use the carbs off the 250C, which seem OK.

Believe me, if I had unlimited time (I do have a day job and a family, house, dog, etc.), I would pull the carbs off the 280S, boil them out, have the surfaces trued, etc. and put them back together and test them. But - I need to get the engine/trans out of the 280S and get it on its way to the crusher - Senior Management really wants her side of the garage back. Then I need to get the engine/trans out of the 250C, and the engine/trans from the 280S in, and get the 4-speed working in an automatic car. And don't forget the 280C waiting with its new short block now on a truck from Texas!

BTW. Charles - I have located the stuff I need (pedals, driveshaft, linkage, clutch master) to do the trans conversion.

So, it's not surrender - sort of a tactical retreat - given all the stuff I have on my plate.

I am concerned, though, that Christy and Mark can rebuild and adjust their carbs to perfection and still not achieve satisfactory results because of the warping and vacuum leak problems.

Chuck

And don't forget my note in an earlier post, since the whole manifolds have to come off anyway, you can swap them now, should you really care to hear the 280S run well. At least swapping them will let you test out the combination before you do all the hard work.

-CTH

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Hey Chuck, Its better when you put it that way.
Though I dont envy the upcoming tranny conversion. Glad mine came as a 4speed.

I put my front carb back together today I think I found the source of my greif, a dirty idle jet and ripped secondary diaphram. It would explain the crappy idle and lack of top end. Everything else looked good, except for the crud on the housing. Overall, a good exercise since from the inside out, I'm starting to understand their function a little better. Not that I'm ready to write a book or anything, I slept through much of Fluid Dynamics!

Big question is, do I go through a full breakdown of the rear carb, or just pull the jets and diaphram, clean and reassemble?

I'll keep you all posted after I get a new diaphram in the front.

Mark

Why not just swap the carb sets as a whole manifold assembly. It will cost you the two asbestos o-rings for the exhaust seals.

OBTW, Now would be a great time to order replacement nuts for the manifolds and exhaust, not to mention a new I/E manifold gasket. The right nuts are these cool, deformed brass ones. You'll need 10 for the manifold, get at least 12. Also, You'll need 6 for the exhaust, get 8.

They are 10mm & 8mm respectively.

-CTH

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Charles -

Thanks for the advice.

At the moment, I am leaning towards just lifting the carbs off the 250C, because the 280S (God bless it) has functioning, non-leaking heat risers. They are the old style, but they work and the coil springs appear to be new.

Chuck

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe

For final assembly, that sounds fine. For just playing with the 280S in place, don't worry about it, since you'll take things apart yet again for the real swap.

-CTH

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I would go ahead and DO the rear carb right. I mean you have it off of the car...might as well..

GO Quins....heehee

~Christy