Edelbrock 1410 stalls unless kept at 1/4 throttle
09-18-2023 | 04:15 AM
#21
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Joined: Feb 2009
Posts: 8,356
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From: NW Michigan
Edelbrocks are easy, but you gotta do step by step.
First, we will ASSUME your ignition timing is IN THE BALLPARK for now.
Edelbrock is good w 5 to 8 psi.
If the carb is brand new out of the box, then it will probably be a touch on the rich side, which is safe.
You need a vacuum gauge, and a timing light.
Hook the vacuum gauge to the fulltime vacuum port (not the "ported vacuum"). Count the number of turns required to close the idle mixture screws, and then put them back where they were.
So, for initial settings, do whatever you have to do to get the engine up above 140 degrees or so. THEN adjust the choke fully open for now. Then set idle stop screw to 800 rpm.
Take note of the vacuum reading.
Then turn the idle mixture screws IN 1/4 turn and see of the vacuum drops or rises. If no big change, turn another 1/4 turn. If vacuum is weaker, then go back to the original settings and 1/4 turn OUT and watch vacuum. Keep turning (both in 1/4 increments) until you see MAX vacuum.
If, at any time during this, the idle increases past 1,000 rpm, readjust the idle stop screw back down to 800 rpm. Keep repeating the process until you've found the setting that gives max vacuum at 800 rpm.
NOW look at where you ended up - if you landed at more than 2.5 turns out, then it is likely that your jetting may be too lean on the "needle down" position (you can refer to the jet/needle chart that came with the carb).
Once you get your idle mix set, then move your timing around, also watching the vacuum gauge. Once you find the timing setting that gives you best vacuum at 800 rpm, (again, you may have to adjust the idle stop screw) use the timing light to see where it is. Write it down.
But if you are using the normal V8 Module on your T Bolt ignition you should not run more than 10 BTDC.
Let's say you end up at 10 BTDC and 2.5 turns out on your idle mix screws at max vacuum at 800rpm.
Now you should go drive around at mid-cruise and be sensitive about listening and feeling for rich/lean conditions.
If you're happy with that, then set your choke per normal procedures (it has to be done when fully cold).
First, we will ASSUME your ignition timing is IN THE BALLPARK for now.
Edelbrock is good w 5 to 8 psi.
If the carb is brand new out of the box, then it will probably be a touch on the rich side, which is safe.
You need a vacuum gauge, and a timing light.
Hook the vacuum gauge to the fulltime vacuum port (not the "ported vacuum"). Count the number of turns required to close the idle mixture screws, and then put them back where they were.
So, for initial settings, do whatever you have to do to get the engine up above 140 degrees or so. THEN adjust the choke fully open for now. Then set idle stop screw to 800 rpm.
Take note of the vacuum reading.
Then turn the idle mixture screws IN 1/4 turn and see of the vacuum drops or rises. If no big change, turn another 1/4 turn. If vacuum is weaker, then go back to the original settings and 1/4 turn OUT and watch vacuum. Keep turning (both in 1/4 increments) until you see MAX vacuum.
If, at any time during this, the idle increases past 1,000 rpm, readjust the idle stop screw back down to 800 rpm. Keep repeating the process until you've found the setting that gives max vacuum at 800 rpm.
NOW look at where you ended up - if you landed at more than 2.5 turns out, then it is likely that your jetting may be too lean on the "needle down" position (you can refer to the jet/needle chart that came with the carb).
Once you get your idle mix set, then move your timing around, also watching the vacuum gauge. Once you find the timing setting that gives you best vacuum at 800 rpm, (again, you may have to adjust the idle stop screw) use the timing light to see where it is. Write it down.
But if you are using the normal V8 Module on your T Bolt ignition you should not run more than 10 BTDC.
Let's say you end up at 10 BTDC and 2.5 turns out on your idle mix screws at max vacuum at 800rpm.
Now you should go drive around at mid-cruise and be sensitive about listening and feeling for rich/lean conditions.
If you're happy with that, then set your choke per normal procedures (it has to be done when fully cold).
09-18-2023 | 05:45 AM
#22
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Joined: Jun 2020
Posts: 524
Likes: 188
From: Holland MI
I had a very similar issue with a merc carb, and also a holley. The merc carb turned out to be a vacuum leak (still leaked with RTV on both sides of old gasket, new gasket with NO RTV fixed it)
the Holley ended up having the incorrect gasket installed between the bowl and the base.
the Holley ended up having the incorrect gasket installed between the bowl and the base.
09-20-2023 | 05:22 AM
#24
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Joined: Sep 2018
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09-21-2023 | 01:11 AM
#25
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Joined: Sep 2001
Posts: 5,769
Likes: 151
From: tn
Generally, at and around idle there is zero concern about needles lifting. WHEN the needles lift is one of the last tuning steps in a car. A boat is a constant load application which does demand that you get at least "in the ballpark" with the springs before fine tuning.
Properly working, the throttle plates will be very nearly shut at idle and the main jets and needles will have a minimal effect on your idle mixing. If things are WAY out of whack, you can come across examples of the throttle plates needing to be open partially into the transition slots to idle but an out-of-box Edelbrock on a near-stock motor won't fall into that category.
09-21-2023 | 02:46 AM
#26
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Joined: Nov 2004
Posts: 14,163
Likes: 3,721
From: On A Dirt Floor
