Jim, at least it's not smoking. Guess that is getting worn out but I still feel for your experience. Anyways years ago when faced with the prospect of kitting mercedes twin zeniths because of all the varnish buildup from gas residue from evaporation in storage. I had one of my insane episodes. I thought gas engines would run on straight laquer thinner quite well. So I just opened the carb feed line under the car and put the feed line in a quart can of laquer thinner. I already knew it dissolves dried gas residue like crazy. Made sure the carb was run out of gas first of course. This is advisable as you do not want your thinner mostly going back to the tank in the return line. Cranked it until bowl etc was filled with the thinner and car started. Shut down and let soak until thinner started to come out the idle screws passages. About 1/2 hour till the first one started by the way. Maybe 15 minutes after till the second one did. Same result as if i had taken the carbs apart, carb cleaned them, and kittted them. No kidding and have used it several times since and will probably again. The only concern I had was if it might attack the floats if they were plastic. That as never turned out to be an issue with carbs that have them. It is probably the limited short exposure to the thinner. Never will understand why others have not done this as far as I know. But if you own cars with two zeniths it is a lot easier. By the way in all of my cases the carbs were much worst than your symptoms as there was no idle even possible on some. Plus the bonus here was in most cases the carbs were in better shape after the cleanout than the last time they were driven. Do not expect this to repair an accelerator pump for example or white metal corrosion problems. But to get rid of the dried gas varnish it seems infallable. Also great for gummed up small carbs. Labour saving, effective and my favorite cheap solution. Pun intended. Since your fuel pump is in the gas tank you might have to run the carb out of gas and feed the laquer thinner down the small tube in the throat to fill the bowl and passages. From your description the idle passages are not totally closed although the thinner would eat through fast enough if they were. But it will work exactly the same. Nothing to loose in my opinion.

One of the most creative solutions I've ever run across. I love it! I'll use it the next time I have to start the Atomic 4 in my sailboat, which has been sitting for a few years.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Kerry, I would just fill your carb with diesel or another light oil for storage. The thinner does not remove any metal so is not too agressive. But the curse of the white corrosion in the die cast passages is too great to risk. On the very small carbs I have lost several because of it. It was in places I could not get to internally in the castings. Just run your carb out of fuel and fill it through the throat tube. Only takes a few minutes. My other approach is for guys like me that think the car is only going to be out of service for a short time and it becomes years. Or for an aquired car that has sat a long time.

Another great idea. I've always used fogging oil but never considered filling it up with oil.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

That does sound like a heck of a good idea. So, in true stick-man form, I'm attaching a carb pic with several portions labled. Where would I pour the laquer thinner? "B" seems to loop around and come out of "B-1" if I spray carb cleaner in it.

Attached Thumbnails

 

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Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

You need to put it down the bowl vent. I think b-1 could be a bowl vent, give it a try. It shouldn't hurt. It looks to me as if the bowl is to the left side of the carb, at least that's where the fuel line seems to go in. You could pull the fuel line, attach another line and feed the laquer thinner down that line into the bowl.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

I believe B is the bowl vent and B1 is an overflow. To get the most thinner in, you need to disable the fuel pump, start the car and let it run until it quits. Then put the thinner in B until it comes out B1. Maybe you can put vicegrips on a rubber fuel line to stop the flow of fuel. What ever you need to do to stop fuel from keeping the bowl full of gas.

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84 500 SEL (307,xxx miles)

I believe the guys have got it right. To disable the electric pump just pull its fuse perhaps. A large syringe with no needle or something simular even a tiny funnel should suffice to load the carb. I would leave the carb for 3/4 of an hour and try the engine. If better but not good one more time. I do not know the actual composition of american gas versus ours. Other than it is cheaper unfortunatly. Let us know if your results are ok. Unfortunatly there is also a chance something might have seized on,around or in that carb as well but hope not..