diagnose output port condition, carbed 6 gurus |
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diagnose output port condition, carbed 6 gurus |
mskala |
Feb 28 2004, 11:32 PM
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#1
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R Group: Members Posts: 1,927 Joined: 2-January 03 From: Massachusetts Member No.: 79 Region Association: None |
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Carl |
Feb 29 2004, 01:41 AM
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#2
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Ummm ... what? Group: Members Posts: 781 Joined: 17-January 03 From: San Jose, CA Member No.: 163 Region Association: Northern California |
Looks like oil getting past the guides to me.
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John |
Feb 29 2004, 02:22 AM
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#3
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member? what's a member? Group: Members Posts: 3,393 Joined: 30-January 04 From: Evansville, IN (SIRPCA) Member No.: 1,615 Region Association: None |
I agree. It looks like oil.
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Gint |
Feb 29 2004, 09:30 AM
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#4
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Mike Ginter Group: Admin Posts: 16,095 Joined: 26-December 02 From: Denver CO. Member No.: 20 Region Association: Rocky Mountains |
(IMG:style_emoticons/default/agree.gif) Mine look worse than that. #6 in particular. I can actually see a small puddle of oil.
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mskala |
Feb 29 2004, 10:25 AM
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#5
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R Group: Members Posts: 1,927 Joined: 2-January 03 From: Massachusetts Member No.: 79 Region Association: None |
I guess that makes sense. Does the oil somehow limit carbon buildup
or are they also running lean (probably idle)? Whenever I set the carbs I can get all the air flow the same, but turning the mixture screws is a bit of black magic. (IMG:style_emoticons/default/headbang.gif) Thanks! |
Carl |
Mar 1 2004, 12:33 PM
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#6
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Ummm ... what? Group: Members Posts: 781 Joined: 17-January 03 From: San Jose, CA Member No.: 163 Region Association: Northern California |
Mark,
Explain the "Black Magic" comment. You can't get the screws to turn? If they turn there's no response? The most common result of lean idle jets is a stumble to the engine on acceleration and spitting back through the carbs at idle. What do the plugs look like? I agree with your question about the oil in the exhaust ports. Ordinarily you'd be trailing smoke with any significant quantity of oil leaking past the exhaust guides and you'd see carbon in the port. So, it could be lower temps in those cylinders due to ?? guessing here -> can't be running lean since that's hotter and oil would burn so, maybe these cyls are running rich and the oil is providing enough of a coating that the carbon is not sticking to the port walls they way it is in the others? |
Gint |
Mar 1 2004, 05:18 PM
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#7
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Mike Ginter Group: Admin Posts: 16,095 Joined: 26-December 02 From: Denver CO. Member No.: 20 Region Association: Rocky Mountains |
Check for an air leak. Infamous worn throttle shafts most likely. Mine are going to Eurometrix.
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mskala |
Mar 1 2004, 05:18 PM
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#8
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R Group: Members Posts: 1,927 Joined: 2-January 03 From: Massachusetts Member No.: 79 Region Association: None |
What I mean is that you're supposed to first assume that turning
all the mixture screws the same amount from closed will be pretty much the same. Then turning them until max rpm, it's not easy since the rpms are changing a little all the time anyway. And you won't see the results until looking at plugs or ports. I don't like to pull plugs, especially before valve adjustments. Haven't looked in a year (~4k miles) |
Carl |
Mar 1 2004, 08:05 PM
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#9
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Ummm ... what? Group: Members Posts: 781 Joined: 17-January 03 From: San Jose, CA Member No.: 163 Region Association: Northern California |
Mike's got a good thought. If the shafts are leaking air (as mine do, also) the idle doesn't want to settle down much.
It's pretty tough to set the idle mix if the idle isn't steady. Did you try squirting some carb cleaner around the shaft ends? Just out of curiousity, do you still have the stock venturis in the carb? Mine had been changed to a larger size a long time ago and I recently swapped them back. It's interesting the change that it's made to the engine at idle. It doesn't make logical sense but the engine seems to be better behaved even at idle. |
krk |
Mar 1 2004, 08:15 PM
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#10
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Senior Member Group: Members Posts: 997 Joined: 27-December 02 From: San Jose Member No.: 22 |
Carl,
You swapped out your primaries? kim. |
J P Stein |
Mar 2 2004, 03:49 AM
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#11
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Irrelevant old fart Group: Members Posts: 8,797 Joined: 30-December 02 From: Vancouver, WA Member No.: 45 Region Association: None |
A couple of thoughts......which seldom have much worth. (IMG:style_emoticons/default/laugh.gif)
Look at the plugs. Usually, the plug will confirm what the light colored valve is telling you....lean....maybe too lean.....or maybe they all should be that color (IMG:style_emoticons/default/confused24.gif) I prefer rich...all things considered. Not the most power ("if you wanna be mean, ya gotta be lean"....name that old time drag racer), but safer. Carb tuning is a black art till you understand how to do it....then it's merely voodo. I keep a supply of chickens.....couple of frogs...oh, nevermind. |
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