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Wanting to upgrade carburetor on 1969 BMW 1600


rightshoes

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I have a 1969 BMW 1600, and it currently has a Weber 34 ICH carburetor (single barrel) on it. I've rebuilt the carburetor twice, and it still idles very high and won't run unless I keep the choke on. I've adjusted the fuel/air mixture, and just can't seem to get it right. I think the carb is just old. Instead of replacing it with another Weber 34 ICH, I thought this would be a good opportunity to get a performance carb instead.

I've done some research and I'm looking at replacing it with a Weber 32/36 DGV (manual choke). This is a two barrel carburetor, which means I'll have to get a new intake manifold as well.

From what I've read, I can't just use any intake manifold from a BMW 2002 because the intake holes are slightly smaller on the 1600. It sounds like there's a German company that makes a two barrel intake manifold for the 1600. It is a Cannon manifold, model 99004-095.

I'm leaning towards the DGV (manual choke) because my current carb is manual choke and I think it would require less work to make the conversion (I'm an amateur mechanic).

I'm interested if anyone has a 1600 and has upgraded to this same carburetor, or if anyone sees a potential problem with my plan.

Thanks in advance for your help.

Ryan

'69 BMW 1600

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Ryan,

I had a '71 2002 many years ago and decided to try the Weber 34ICH after the throttle body of the 1 barrel solex went south; I should have replaced with another 1 barrel Solex, didn't really care for the 34ICH. If you go 2 barrel, just do the manifold swap and get a 32/36; you should be able to get the manifold from someone here on the board.

Tim

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You'll need a twin choke manifold from an e21 m10 - pretty common in Europe, and cheap. There's another thread about this recently, have a search.

Yup, an E21 316 among other carbureted Euro E21s have 2bbl intake manifolds with the smaller ports for the 118 style head. I've got one myself.

http://realoem.com/bmw/showparts.do?model=2711&mospid=47166&btnr=11_0799&hg=11&fg=40

Being from what would be a grey market car in the US they're quite rare over here; so it's best to ask around on the British '02 Forum...

http://www.02forum.co.uk/

Though I never did lie the quality of the Cannon conversion intake, it does have the correct casting to accept the original 1bbl early style coolant hoses....

HTH

Tom Jones

BMW mechanic for over 25 years, BMWCCA since 1984
66 BMW16oo stored, 67 1600-2 lifelong project, 2 more 67-8 1600s, 86 528e 5sp 585k, 91 318i
Mom&Dad's, 65 1800TiSA, 70 2800, 72 2002Tii 2760007 orig owners, 15 Z4 N20

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It sounds to me like the idle jet is plugged up with a piece of dirt or debris. The same thing happened to my 2002 when it had a single 34 on it.

You can simply remove the idle jet, clean it out good, make sure you can see through it and put it back in. You should be good to go.

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Good Luck,

Mike (#87)

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I've got an almost brand new 32/36 DGAV (water choke) that I'm trying to get rid of if you're interested. It's got less than a thousand miles on it. I bought it new last summer and about a month later decided to convert to fuel injection.

That said, I probably wouldn't have good advice on upgrading carburetors - I'm sick of em personally.

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I agree with Mike and Lorin -

save mucho money and time

Fix your present carb

remove all the jets - read any weber site for a break down drawing

showing you the location and size of jets you should have

order new jets as needed

pay close attention where any tiny rubber o-rings belong

check the float level and needle and seat condition

get this carb fixed right

it will yield good power, great fuel mileage

you'll smile

proper valve adjustment, proper point dwell angle, and timing setting FIRST!

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Thanks for all of the great advice. I've decided to give my 34ICH another try before dumping money into a new carburetor and manifold.

I found and pulled out the idle jet. It looks pretty clean, but I did notice that it is connected to a solenoid, with a wire running to the ballast resistor. After further research, it sounds like this solenoid is an idle shut off solenoid. From what I've read, it sounds like my problem could very well be a bad idle shut off solenoid. The car runs (idles high) when I have the choke on, but when I turn it off it just dies, like it's not getting any fuel.

I wasn't able to quickly locate a replacement idle shut off solenoid on the Internet. Does anyone know where I can find one. Or better yet, can I get rid of the solenoid and just use an idle jet and idle jet screw like I've seen in many of the diagrams.

Thanks again for all of your help!

Ryan

'69 BMW 1600

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After failing to find a new fuel shut off solenoid on-line, I went into the local import parts store / Weber dealer to see if I could get one. The guy I talked to didn't have one and couldn't order one, but he suggested that I test the one on the carb and told me how to do it.

I pulled out the solenoid, unplugged the wire, turned on the ignition, grounded the body of the solenoid, and then reconnected the wire to the solenoid. When I did so, the solenoid did make a "shutting" noise, and I tested it multiple times.

I've concluded that the solenoid is indeed working, so that at least narrows it down. I got out my air compressor, and blew the heck out of the idle air jet and any other orifice I could find on the carb. I started the car, turned off the choke, and readjusted the air/fuel mixture screw and now I can at least get the car to run without the choke on. It doesn't run awesome (the idle seems to fluctuate), but it seems to be running better.

My next task is to make sure the timing is right. And then maybe make sure the jets in the carb are right for my car. Now I just have to figure out how to do those...

Ryan

'69 BMW 1600

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  • 8 years later...

I recently bought a brand new weber 34 ICH from Redline (kit K909)

It comes with vacuum hose to connect with ignition (hose is about 1 ft to short).
3/8 gas line ( solex has 1/4 inch) Fuel pump is also 1/4inch

I went for the weber because my solex was just worn out and the weber should be an easy replacement.

The original air-filter housing didn't fit over the weber, had to remove the rubber and make the opening a little bigger.

Then i noticed that my air-filter housing was sitting to high and was touching my hood. (the Weber is 1inch higher).

I connected the wire from the cut-off solenoid to 12V feeding wire that runs to the brake light switch.

I modified the air-filter housing and gain about 3/4 inch. enough to close my hood.

The engine starts really good and runs idle beautiful but when i drive it is holding back. 

I noticed that it runs much better when i pull out my choke. I think the main jet is to small. 

So what is sold as an easy replacement kit for the BMW 02 Solex is not easy at all!

Anyone has experience with the right jets for this carb?
In the documentation provided with the Weber it says that the max fuel pressure is 3.5PSI In the BMW specs i says that the mechanical pump gives 4.27PSI at 4000rpm.

20190720_093030_resized.jpg

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The Weber 34ICH is too small for either a 1600 or a 2002. It has a very small 34mm throttle body, which is way too small for our cars. In comparison the single barrel Solex 38-40PDSI used on the 1600s and 2002s has a 38mm throttle body on the 1600 version and a 40mm throttle body on the 2002 version. The Weber 34ICH is more tailored for a small engine in the 1,000cc-1,300cc size. I've tried the 34ICH  on my 69 1600, and it works great at idle, but the lack of performance in comparison to the stock carb is very noticeable. In your case, you probably have a clogged or defective idle jet. 

 

The Weber 32/36 is also problematic on the 1600 and less so on the 2002. I've also tried this route with mixed results. First of all you need to find a manifold from an e21 1600cc 316. And, once you get that sorted out, you need to  replace the jets on the 32/36, as your car will fall flat on its face once you depress the accelerator. It will idle great, but the stock out of the box jets on the 32/36 will not work on the 1600 due to an extremely lean condition. They work on the 2002, though, but they are not ideal for that motor either. It's just too much air for the 1600. So, you need to go up on the fuel jets and come down on the air jets for both. primary and secondary. On the primary you will need to go up from the 135 main fuel to about 150 or 155. And, you'll need to get the main air on the primary down in the 160 or 165 range. A similar adjustment is needed for the secondary. This is as  what I had to do to get rid of al the stumbling, but my mpg suffered as I only got about 17mpg -19mpg. In the end, I settled for a properly functioning original Solex 38-40PDSI. But, on most 50+ year old single barrel Solex carbs, the throttle shafts are sloppy leading to poor idling. You can sort out the problems with the original Solex single barrel, but you will need the assistance of a carb shop, or you can start fishing for the parts yourself.

 

Slavs

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