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Chuff! Fluffing on takeoff. |
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DaemonForce
AMC Addicted Joined: Jul/05/2012 Location: Olympia, WA Status: Offline Points: 1070 |
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It's always a good idea to check your jet size, alignment and run of metering before during and after an overhaul. The issue with these carbureters as core rebuilds is their specific assignment to an engine that may not be an exact fit in another. My grandfather was all about the Motorcraft 2100 and I prefer the Holley Demon and Rochester Quadrajet series as they offer easier tuning despite more complicated building and more things to check. When you have choices on a rebuild, it makes sense to compare venturi sizes and jetting. When the jetting is too big, the engine is in a forced state of rich burn, prone to flooding and hesitation among other oddities. The chuff you had before with the bigger jets was most likely a liquid fuel dump combined with low air volume. Did you have low vacuum before the changeout? Do you still have low vacuum?
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990V8
AMC Addicted Joined: Oct/07/2016 Location: Gloucestershire Status: Offline Points: 787 |
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The carb I bought was supposed to have been rebuilt for this engine. I sent him the spec from the TSM. Guess he thought it would be near enough. So either I go through it and then buy any parts that are wrong, or just go on with it as is. Perhaps a session on a rolling road so the mixture can be checked - there is one 20 miles away where they claim to have Holley expertise.
The only time I looked at vacuum was when I was fixing the wiper motor and vacuum pump. Idle vacuum iirc was around 16in Hg measured on the manifold, at the vac pump takeoff. Ivor |
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63 Canadian Ambo 990 V8 327
Lightweight V8 SIII Shopping Trolley |
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Boris Badanov
AMC Addicted Joined: Dec/14/2013 Location: NH USA Status: Offline Points: 4209 |
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Setting idle mixture with a vacuum gauge is good.
Setting timing by ear or with a vacuum gauge is begging for disastrous detonation. |
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Gremlin Dreams
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990V8
AMC Addicted Joined: Oct/07/2016 Location: Gloucestershire Status: Offline Points: 787 |
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Revisiting this thread after a while, I just rebuilt the supposedly rebuilt carb.
Not only did it have an old and leaking fuel needle and seat, and toasted gaskets, but the wrong power valve. Should have an 8.5", it had a 6.5". Rebuilt? Don't think so. And it still had the wrong accelerator jet. That was my fault; I put a 21 in there, but rereading the tsm, I see I confused it with the 10 series, it should have a 28 so that's what I put in now. I torqued all the hold-down nuts with a slim extension and a crow's foot. Idle vac now is 18in, which I see is better than I had three years ago. Haven't taken the car out on the road yet, it's raining. Perhaps next week. Ivor
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63 Canadian Ambo 990 V8 327
Lightweight V8 SIII Shopping Trolley |
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farna
Supporter of TheAMCForum Moderator Lost Dealership Project Joined: Jul/08/2007 Location: South Carolina Status: Offline Points: 19610 |
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Well, it should certainly run much better now, and probably not use as much petrol (as you say over there...)!!!
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Frank Swygert
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990V8
AMC Addicted Joined: Oct/07/2016 Location: Gloucestershire Status: Offline Points: 787 |
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Did 300 miles over the holiday.No fluffing at all. It just takes off without hesitation. Very pleased.
And still doing around 19mpg imperial. Now, on to the next job. Ivor
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63 Canadian Ambo 990 V8 327
Lightweight V8 SIII Shopping Trolley |
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rockAMX
AMC Addicted Joined: Sep/16/2011 Location: Lethbridge AB Status: Offline Points: 983 |
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Was it rebuilt by a guy in a shed? Now you know how to rebuild your carb, forget the guy in the shed.
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DWR
1968 AMX |
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