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Post by magikbus on Sept 26, 2020 12:12:12 GMT -8
Hi all. Notice to all who have dual carbs. I've been having trouble getting my 2L dual carb engine to idle properly without mini backfires rough idle and stalling. I"ve ruled out that it isn't a vacuum leak after cracking my head numerous times using a spot lighted magnifier to see every square millimetre of the engine compartment. Not sure at what rpm this is happening I guess I should hook up a tach and see. I did notice the mechanism I'll try and post that shows a tab on the large rod which connects the accelerator cable with both carbs to activate the carb acceleration stuff. Fixed to the left hand carb is a mount containing a threaded hole (M8 x 1.25) which lines up perfectly with the tab on the large rod. This mechanism if it had an adjustable bolt in it would make a perfect idle adjustment system. Is this stock, or is it something on a third party dual carb setup that isn't necessary on these engines? Stan, curious in Ladysmith.  |
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Post by Volktales on Sept 26, 2020 21:22:15 GMT -8
There was once a dashpot there which slowed the throttle valve from closing quickly when you back off the throttle. An emission control device, and 99.9 percent of them are now missing. Just like your air pump on your '74. Last saw one of those 20 years ago...
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Post by CrazyBrit on Sept 27, 2020 8:01:30 GMT -8
I think he should try a pair of Webers and a 009...
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Post by magikbus on Sept 27, 2020 18:27:08 GMT -8
Oh Mark, you've just brought up a topic that gave me nighmares for years. I had a single Weber on my old '74 (Magikbus) hooked up to an 1800 cc engine. It took us all the way back to Nfld and back, twice and would never idle for more than 5 seconds. We hit Seattle coming from the East at 5pm one Friday afternoon and took 2 yours to get West to the "5" and North to the Seattle limits due to traffic jams. I was exhausted doing the Rolf Harris 3 legged act. I had previously tuned up the engine numerous times, changed jets to various other sizes etc etc but no luck.
Stan
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Post by CrazyBrit on Sept 27, 2020 19:39:27 GMT -8
That's because you only used one! My Ghia runs terribly with it's dual throat Weber, but the bus runs beautifully with the twins. That said, they do take a bit of setting up.
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Post by Rob Sannes on Sept 28, 2020 6:10:49 GMT -8
I had a 2bbl weber on my 71 bus ran like crap wouldn't idle at first. I bumped up the idle jet fixed 2 vacuume leaks. It ran a bit rich but was good for me. l mean it started idled ran the rpm range. And got worse milage than the pict34 I replaced, but with the 009 that was in my 71 that was installed by the previous owner it was smoother and felt better by the s.o.t.p. dyno. People bag on those carbs because they will install, one often incorrectly on a sick /worn out motor and it doesn't run correctly. Working heat risers are a must and a challenge when running a aftermarket extractor. The combo and attention to detail are important. If I had just maintained my motor correctly and fixed the vacuume leak in the first place I could have saved $125.00 1988 us dollars kept my 34 and neve known a thing about the Weber DGAV but after a lot of oldschool book work and talking to a lot of guys, I got it to work. Good enough reason for some to keep it stock I should have. It's too late for me now. 2 litres with no heaters!!!!  |
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Post by CrazyBrit on Sept 28, 2020 7:48:37 GMT -8
The Ghia idles and drives well enough, but it has a huge flat spot and I find that I have to really feather the throttle until it is well warmed up. It is also quite lumpy at idle until warmed through. It's paired with a Mexican 009, which might be part of the problem, and yes, the engine is getting tired. I will be replacing the carb' in the near future. I am hoping to do a top end rebuild yhis winter, once I have finished the work that I want to do on my bus.
Perhaps it needs some more capacity...😀
BtW, your oval looks fantastic in that photo.
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