Edelbrock 1806 Tuning
12-30-2010, 09:38 AM
#11
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Ya your definitely running rich if your eyes are burning. You should pull the plugs as Starfury said and check if they are black and sooty they may be fouled. If the plugs are fouled you will have to replace them and then go through the normal steps playing with the timing and carb fuel mixture adjustments. Like someone mentioned earlier old school trial and error.
12-31-2010, 06:40 AM
#12
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Damp tailpipes don't mean anything either. Water is a natural byproduct of combustion.
But if it's smelling rich, then yes, something's definitely wrong. Doesn't mean it's your cruise mode, though, and the clean plugs support that. Could be your step-up springs are too soft (I'll cover that in a minute), or could be the power mode is too rich. And at idle you tune with the idle mix screws. The jets and rods don't really affect idle mix.
First thing's first, set the timing properly. If your timing's off, you'll be chasing your tail forever trying to get the carb dialed in. 8-10* initial, 30-34* total, all in by ~3k. That should get you in the ballpark.
Once the timing is set, set the idle mix. A vacuum gauge really helps here, but you can do it by ear as well. Once the idle mix is set, then worry about tweaking the rods/jets.
The one problem that I seem to notice with these carbs out of the box is that they tend to come with 7" step-up springs, which is a bit soft for many performance motors. The power mode kicks in too early, drawing too much fuel into the motor before it needs it. Drop a 4" or 5" spring in and it may help things a little.
But if it's smelling rich, then yes, something's definitely wrong. Doesn't mean it's your cruise mode, though, and the clean plugs support that. Could be your step-up springs are too soft (I'll cover that in a minute), or could be the power mode is too rich. And at idle you tune with the idle mix screws. The jets and rods don't really affect idle mix.
First thing's first, set the timing properly. If your timing's off, you'll be chasing your tail forever trying to get the carb dialed in. 8-10* initial, 30-34* total, all in by ~3k. That should get you in the ballpark.
Once the timing is set, set the idle mix. A vacuum gauge really helps here, but you can do it by ear as well. Once the idle mix is set, then worry about tweaking the rods/jets.
The one problem that I seem to notice with these carbs out of the box is that they tend to come with 7" step-up springs, which is a bit soft for many performance motors. The power mode kicks in too early, drawing too much fuel into the motor before it needs it. Drop a 4" or 5" spring in and it may help things a little.
Last edited by tx65coupe; 12-31-2010 at 06:44 AM.
12-31-2010, 06:42 AM
#13
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Yes if the eyes are stinging you are dumping raw fuel. First thing you need to do is get correct fuel pressure. 4.5 psi is what those edelbrocks want. Not 6. Use a regulator. Once that is done check float levels and what was said about the secondaries. Your floats might be stuck. You usually see that when fuel drips out of the boosters. If you gave a vacuum gauge use that to set mixture and step up spring like starfury said.
I forgot to mention, I am running the Edelbrock fuel pump that is recommended for the carb.
Last edited by tx65coupe; 12-31-2010 at 06:46 AM.
12-31-2010, 07:51 AM
#14
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I checked the owners manual. http://www.google.ie/m/url?client=sa...7wncCZmU3unWuQ give that a good read. Here it says to set to 5.5 and 6 is absolute max. So you might be borderline ok. However still set the floats. The manual states how to. Maybe you have a sticky float which is not uncommon to those carbs. You'll see that with very high level or fuel spilling from booster at idle
12-31-2010, 08:28 AM
#15
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01-24-2011, 11:49 AM
#18
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No problem w/ 14* initial. I've used 6 to 18 initial on various engines.
The all in total advance is critical. Too much and may damage engine on a high speed pass. 32-36 are common sbf all in total advance numbers.
"6psi max fuel pressure" may or may not be marketing related. More than one pressure gauge has registered more than 6 psi on edelbrock 6 psi max pump.
I have a huntch that a healthy edelbrock carb would handle 7psi w/o flooding.
My gauges not properly calibrated so can't verify.
My 1405 edelbrock had a rich idle problem that I chased around. Changed fuel pump, set floats, played w/ springs, etc. to no avail. Finally solved the problem by rebuilding carb; small oriface was plugged.
Must tune idle mode, cruise mode, 2bbl acceleration mode, and WOT modes separately.
If idle smells overly rich 1st step is to adjust to lean smooth idle. Verify plug burns off white. Some like advace connected to full time vac port; like me. My 67 cam likes as much initial advance as possible. 2nd step is to check for carb flooding.
Many aftermarket cams will not efficiently burn fuel during idle thus have a somewhat richer smelling exhaust than OEM.
Make sure AVS is adjusted to original factory settings until you are ready to fine tune WOT.
If AVS is adjusted out of spec it can run rich.
Last edited by 001mustang; 01-24-2011 at 08:47 PM.
01-24-2011, 09:56 PM
#19
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I forgot to mention this before. The vacuum gauge fluctuated a little. Is the vacuum gauge supposed to have a steady reading?
I figured the cam could cause a slightly rich idle, but the cam is not radical at all and is pretty mild.
I rebuilt the carb about 9 months ago even though it was only about a year and a half old and only had 3000-4000 miles on it because I had some major issues. I did it accoriding to Edelbrocks specs, so all of that should be good.
I figured the cam could cause a slightly rich idle, but the cam is not radical at all and is pretty mild.
I rebuilt the carb about 9 months ago even though it was only about a year and a half old and only had 3000-4000 miles on it because I had some major issues. I did it accoriding to Edelbrocks specs, so all of that should be good.
Last edited by tx65coupe; 01-24-2011 at 10:00 PM.
01-24-2011, 10:25 PM
#20
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rougher the cam...rougher the idle...rougher the vacuum
i tune idle by ear.
mark lean idle w/ sharpie(cw till gets rougher than good idle)
mark rich idle w/ sharpie(ccw till gets rougher than good idle)
When tuning carb modes via plug readings i use lean idle setting to keep plug clean between runs.
otherwise i run between lean idle and rich idle.
lean idle can be verified by bright white #1 plug.
can you achieve lean idle via idle mix screws???
i tune idle by ear.
mark lean idle w/ sharpie(cw till gets rougher than good idle)
mark rich idle w/ sharpie(ccw till gets rougher than good idle)
When tuning carb modes via plug readings i use lean idle setting to keep plug clean between runs.
otherwise i run between lean idle and rich idle.
lean idle can be verified by bright white #1 plug.
can you achieve lean idle via idle mix screws???
Last edited by 001mustang; 01-25-2011 at 10:43 AM. Reason: meant to communicate rougher the vacuum