 Tuning dual Webers, Looking for input in the PNW |
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| TC 914-8 |
 Dec 8 2011, 09:53 PM
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#1
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Senior Member  Group: Members Posts: 812 Joined: 23-May 08 From: Sequim, WA Member No.: 9,090 Region Association: Pacific Northwest 
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I just found out my wifes coworker, The Dr Vet's husband, has a 75 2.0 with a dual Weber downdraft conversion. I stopped by last weekend to take a look. it has some minor electrical issues which I should be able to sort out fairly quick with proper diagnostics. Horn, lights etc..
One of his main concerns is mis firing and sputtering during acceleration. It is a fairly clean set up bought from a guy in Bremerton back in 2000. I forgot his name but should be active on this site. so under slight acceleration, reving the engine it sputters around 2500 RPM. with no gauges or tools I noticed the F/A screws on the driverside carb were out different ratios. I gave them a slight adjustment and it seemed to help. I figure we need a air flow meter to put over each venturi and dial in each barrel evenly. (IMG:style_emoticons/default/idea.gif) Being a V-8 guy I would slap on a vaccume gauge and adj from there.... I did not see any vacume ports so its all new to me (IMG:style_emoticons/default/confused24.gif) How do you boys dial these babys in? I was also under the impression a stock FI cam is not really compatible running carbs... (IMG:style_emoticons/default/confused24.gif) Shoot me some ideas , once I get him running, I will have a new teener buddy in the neighborhood to tool around with since you Teener Tuesday boys are afraid of coming accross on the ferry (IMG:style_emoticons/default/poke.gif) |
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| 914werke |
Dec 9 2011, 09:51 AM
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"I got blisters on me fingers" Group: Members Posts: 10,119 Joined: 22-March 03 From: USofA Member No.: 453 Region Association: Pacific Northwest
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and there is the old standby...ditch the carbs & put the FI back on it.
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| stownsen914 |
Dec 9 2011, 11:22 AM
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#3
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Senior Member Group: Members Posts: 913 Joined: 3-October 06 From: Ossining, NY Member No.: 6,985 Region Association: None |
Cars that haven't been run much can obviously develop issues, both carb and non-carb related. Syncing up the carbs is a good idea since it's pretty easy to do and can only help.
One thing that would be good to know is whether this problem occurred before, or is it brand new. Rough running at certain RPM sounds like a classic carb circuit transition issue. At 2500 PRM it would probably be the transition from the idle circuit to the main circuit in your carbs. As you probably know, there should be a spring loaded idle circuit adjuster screw on the side of each carb barrel, and they work like a faucet. (To be clear, this is not the idle RPM adjuster that sets the butterfly position at idle, but the fuel adjustment. Also not the idle air adjustment.) Clockwise turning means less gas, counter-clockwise gives more gas. You can move them half a turn at a time (do the same adjustment for all four barrels), and see how it affects the rough running. You should see some difference in running within a couple turns one way or the other. It's also pretty easy to clean jets, which can become clogged with debris or gummed up with old fuel residues. You can try that too. Scott |
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| stownsen914 |
Dec 9 2011, 11:25 AM
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Senior Member Group: Members Posts: 913 Joined: 3-October 06 From: Ossining, NY Member No.: 6,985 Region Association: None |
Oops duplicate post
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Posts in this topic
TC 914-8 Tuning dual Webers Dec 8 2011, 09:53 PM
Ductech I would start with thinking about how long this ca... Dec 8 2011, 10:06 PM
TC 914-8
I would start with thinking about how long this c... Dec 8 2011, 11:52 PM Ductech Some people used old sync gauges that would go ove... Dec 8 2011, 11:59 PM nathansnathan
Some people used old sync gauges that would go ov... Dec 9 2011, 09:40 AM mrbubblehead i use a snail for synchronizing and an innovate ai... Dec 9 2011, 12:07 AM jaxdream Don't forget to adjust the valves before synci... Dec 9 2011, 08:42 AM messix Have I not taught you any thing?
Go give it an I... Dec 9 2011, 11:36 AM J P Stein There are a number of things that could be causing... Dec 9 2011, 11:50 AM pt_700 slightly ot but, i had an old mechanic friend once... Dec 9 2011, 12:48 PM TC 914-8 Wow, thanks guys for all the input, I like the Car... Dec 9 2011, 09:09 PM a914622 Hey i have a snail syncer i could let you use to s... Dec 9 2011, 10:36 PM mrbubblehead
Just a thought but i rigged a vacuum line back o... Dec 9 2011, 10:55 PM TC 914-8
Hey i have a snail syncer i could let you use to ... Dec 10 2011, 01:05 AM |
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