What is this popping sound?, rich or lean? |
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What is this popping sound?, rich or lean? |
derekdenman |
Nov 12 2007, 06:09 PM
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#1
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Newbie Group: Members Posts: 33 Joined: 29-June 07 From: Mckinney, Tx Member No.: 7,852 |
I am hearing a pop sporadically while driving at a constant RPM. Whenever it pops you can feel the engine miss as well. The engine is a very fresh 2056 with dual Dellorto 40’s, mild carb web cam, and a stock 050 distributer. Also it runs strong from idle to about mid throttle but after mid throttle it has no power and goes from a smooth sound to a very low throaty sound. It seems like it is rich due to the lack of power after half throttle but it the pop seems like a lean miss. Any suggestions? Maybe multiple problems?
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degreeoff |
Nov 12 2007, 06:12 PM
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#2
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I like big butts and I can not lie! Group: Members Posts: 1,622 Joined: 9-February 03 From: Booowieeee MD (near DC) Member No.: 275 Region Association: MidAtlantic Region |
Hmm sounds almost like a ignition issue....
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cobra94563 |
Nov 12 2007, 06:20 PM
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#3
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Chris Group: Members Posts: 341 Joined: 1-March 05 From: San Francisco Member No.: 3,696 |
(IMG:style_emoticons/default/popcorn[1].gif)
I'm experiencing something similar (on a different engine). I have an O2 sensor on the exhaust and my mixture is fine thru the range, so I'm thinking something in the ignition. (IMG:style_emoticons/default/popcorn[1].gif) |
derekdenman |
Nov 12 2007, 06:28 PM
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#4
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Newbie Group: Members Posts: 33 Joined: 29-June 07 From: Mckinney, Tx Member No.: 7,852 |
I am running a Crane XR3000 ignition with the LS91 coil. The wires plugs, boots, and cap are all new. One the vacuum advance there are two nipples. One nipple is pulling a vacuum from the manifold. The other (closest to distributer) is not connected to anything.
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Allan |
Nov 12 2007, 06:50 PM
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#5
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Teenerless Weenie Group: Members Posts: 8,373 Joined: 5-July 04 From: Western Mesopotamia Member No.: 2,304 Region Association: Southern California |
Clogged idle jets.
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IronHillRestorations |
Nov 12 2007, 07:00 PM
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#6
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I. I. R. C. Group: Members Posts: 6,719 Joined: 18-March 03 From: West TN Member No.: 439 Region Association: None |
Ed Mayo once told me that half of carburator problems are ignition.
Check to make sure your distributor is getting full advance, and also check your timing at full advance. If that checks out OK, then I'd suspect you might need to go up a size on the main jet. I don't know how much trouble it is to change jets on Dels. |
thomasotten |
Nov 12 2007, 07:16 PM
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#7
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Senior Member Group: Members Posts: 1,545 Joined: 16-November 03 From: San Antonio, Texas Member No.: 1,349 |
Sounds a lot like the same problem I ham having. I'm running Dells too. What are your jet sizes? (IMG:style_emoticons/default/popcorn[1].gif)
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So.Cal.914 |
Nov 12 2007, 07:59 PM
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#8
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"...And it has a front trunk too." Group: Members Posts: 6,588 Joined: 15-February 04 From: Low Desert, CA./ Hills of N.J. Member No.: 1,658 Region Association: None |
QUOTE Sounds a lot like the same problem I ham having. I'm running Dells too. Well theres your problem, I run Webers. (IMG:style_emoticons/default/w00t.gif) |
degreeoff |
Nov 12 2007, 09:12 PM
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#9
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I like big butts and I can not lie! Group: Members Posts: 1,622 Joined: 9-February 03 From: Booowieeee MD (near DC) Member No.: 275 Region Association: MidAtlantic Region |
I am running a Crane XR3000 ignition with the LS91 coil. The wires plugs, boots, and cap are all new. One the vacuum advance there are two nipples. One nipple is pulling a vacuum from the manifold. The other (closest to distributer) is not connected to anything. Ummm dumb question but the other nipple is plugged yes? (IMG:style_emoticons/default/blink.gif) I mean if its not then you'd be getting no vaccum I PrEsUmE? SEE next post.... Ok so I am an idiot......thats what a 009 and soon to be a crankfire system will do to a guy |
Twystd1 |
Nov 12 2007, 09:28 PM
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#10
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You don't want to know... really..... Group: Members Posts: 2,514 Joined: 12-September 04 From: Newport Beach, California Member No.: 2,743 |
If ya plug the other nipple. The advance plate won't move... ya leave it open
Clayton |
Joe Ricard |
Nov 12 2007, 09:31 PM
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#11
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CUMONIWANNARACEU Group: Members Posts: 6,811 Joined: 5-January 03 From: Gautier, MS Member No.: 92 |
These threads are sooooo funny.
What RPM cruising up to 3500 RPM Throttle slightly open. you are on the idle jets feeding though the progression ports. As the throttle opens up and RPM increases the mains start flowing so if you put your foot down and it runs good then it isn't the mains. I bet one partially clogged idle jet. which causes you to run lean. |
thomasotten |
Nov 13 2007, 06:16 AM
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#12
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Senior Member Group: Members Posts: 1,545 Joined: 16-November 03 From: San Antonio, Texas Member No.: 1,349 |
I have heard bad things about that distributer, 050.
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Thack |
Nov 13 2007, 09:47 AM
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#13
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Member Group: Members Posts: 283 Joined: 1-June 05 From: Houston, Tx Member No.: 4,182 |
Sounds like it's lean before you get into the mains. That low/mid throttle transition is tricky with carbs. Does it get better once warmed up?
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Borderline |
Nov 13 2007, 10:49 AM
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#14
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Senior Member Group: Members Posts: 720 Joined: 8-February 05 From: San Juan Bautista, CA Member No.: 3,577 Region Association: Northern California |
Look for a vacuum leak. spray some carb cleaner around the intake manifold and head while the engine is idling & listen for a change in idle speed. I was so sure my new thick universal gaskets couldn't be leaking...........wrong. Also, if the carbs are older, they may be leaking around the throttle shaft.
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