Fuel starve, or something |
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Fuel starve, or something |
arsprod |
Jul 26 2024, 02:56 PM
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#1
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Member Group: Members Posts: 210 Joined: 14-March 15 From: Indianapolis Member No.: 18,519 Region Association: Upper MidWest |
Teeners,
I swapped out the single carb that came with my 74 2.0 for new to me dual Weber 40's. It took a bit to get them jetted and adjusted but it's at least very close. The car runs great - and then it doesn't. With no consistency, it will start to stumble, cough, and backfire. Most of the time it works itself out though seems to be getting worse. I'm befuddled. (IMG:style_emoticons/default/confused24.gif) Here's what I know: - carbs are jetted main 145, air 200, idle 65, venturi 28 - plugs look ok, if anything rich - I don't seem to have any vacuum leaks - steady 3psi fuel pressure - timing and valves adjusted - new plugs Help! thanks Aaron |
VaccaRabite |
Jul 26 2024, 07:43 PM
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#2
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En Garde! Group: Admin Posts: 13,542 Joined: 15-December 03 From: Dallastown, PA Member No.: 1,435 Region Association: MidAtlantic Region |
with 65 idles you are overjetted for a 2.0. At 3K you have both idles and mains pushing fuel to the engine. You may be fouling plugs. BTDT.
Zach |
arsprod |
Jul 27 2024, 07:33 AM
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#3
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Member Group: Members Posts: 210 Joined: 14-March 15 From: Indianapolis Member No.: 18,519 Region Association: Upper MidWest |
with 65 idles you are overjetted for a 2.0. At 3K you have both idles and mains pushing fuel to the engine. You may be fouling plugs. BTDT. Zach Easy enough to try smaller idle jets. I'll actually test the plugs. You're saying that too much fuel going through the transition shows like too lean? |
Superhawk996 |
Jul 27 2024, 11:41 AM
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#4
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914 Guru Group: Members Posts: 6,469 Joined: 25-August 18 From: Woods of N. Idaho Member No.: 22,428 Region Association: Galt's Gulch |
with 65 idles you are overjetted for a 2.0. At 3K you have both idles and mains pushing fuel to the engine. You may be fouling plugs. BTDT. Zach Easy enough to try smaller idle jets. I'll actually test the plugs. You're saying that too much fuel going through the transition shows like too lean? No, it would be rich misfire with the backfire coming from too much fuel being dumped in and it not lighting off until it gets dumped into the hot exhaust system. This is why I’d like to see your plugs. |
arsprod |
Jul 29 2024, 04:55 PM
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#5
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Member Group: Members Posts: 210 Joined: 14-March 15 From: Indianapolis Member No.: 18,519 Region Association: Upper MidWest |
with 65 idles you are overjetted for a 2.0. At 3K you have both idles and mains pushing fuel to the engine. You may be fouling plugs. BTDT. Zach Easy enough to try smaller idle jets. I'll actually test the plugs. You're saying that too much fuel going through the transition shows like too lean? No, it would be rich misfire with the backfire coming from too much fuel being dumped in and it not lighting off until it gets dumped into the hot exhaust system. This is why I’d like to see your plugs. I think I figured it out and Superhawk you were right - ignition. Of course it's something simple and embarrassingly stupid. The points weren't opening, somehow lost the gap. After gapping correctly and readjusting the carbs it's running again. Argh! |
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