Carb Adjustment
#1
Carb Adjustment
I have a new 600 holley on a rebuilt 351w and apparently it is running real rich. oil smells like gas and I smell like gas after I drive it. Just got it out of the shop and mechanics never said anything about adjusting the carb. Should I rejet it? Is it fairly simple? Exhaust blow some white smoke and some sut!
#3
Is it running rich all of the time or under certain conditions? If it ran normal at first, you might check for a stuck float.
Also, if there is enough fuel in the oil, it may be circulating thru the PCV system causing it to be rich. Change the oil before you do anything else. As cheap as a fuel pump is, I would say replace it and see if your problems clear up.
Jason
Also, if there is enough fuel in the oil, it may be circulating thru the PCV system causing it to be rich. Change the oil before you do anything else. As cheap as a fuel pump is, I would say replace it and see if your problems clear up.
Jason
#4
#5
Sound like you need to adjust the floats. Even when new there are a few adjustments needed. First is idle speed then the floats. Then the mixture screws on the sides. The jetting should be fine out of the box box for most applications.
Float adjustment: Bring engine to temp. Open the site plug on the front bowl, its the flat screw on side of the bowl. The fuel should level with the bottom of the site hole. If fuel runs out, the float is too high which could cause your condtion. Turn off engine, loosen the set screw on top of the bowl a little bit, then use a 5/8 wrench and turn the nut under the screw a 1/4 turn clockwise to lower the float. Now tighten the set screw. Start engine let idle for a minute or so and repeat until the fuel is just at the bottom of the site hole. When the front is done go to the rear bowl and do the same.
Hope this helps. Its really pretty simple and will only take about 15 minutes to get them right.
Float adjustment: Bring engine to temp. Open the site plug on the front bowl, its the flat screw on side of the bowl. The fuel should level with the bottom of the site hole. If fuel runs out, the float is too high which could cause your condtion. Turn off engine, loosen the set screw on top of the bowl a little bit, then use a 5/8 wrench and turn the nut under the screw a 1/4 turn clockwise to lower the float. Now tighten the set screw. Start engine let idle for a minute or so and repeat until the fuel is just at the bottom of the site hole. When the front is done go to the rear bowl and do the same.
Hope this helps. Its really pretty simple and will only take about 15 minutes to get them right.
Last edited by 12secondstang; 01-19-2008 at 08:37 PM.
#7
Tell me this, The timed spark vacuum source on the carb is plugged and my distributor is hooked to the small full manifold port on the bottom of the carb. Is this a big deal? Maybe part of my problem??? Here is a link the the carb that I have
http://www.holley.com/data/Products/.../199R10416.pdf
http://www.holley.com/data/Products/.../199R10416.pdf
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#10
#11
Vacuum changes as you move the throttle. low to high, high to low. This helps adjusts your timing advance as demanded by the engine. If you use manifold vacuum at the dist you will not get any vacuum advance when at full throttle and full vacuum advance at idle/no throttle. This is almost reverse of what you need. That is why you use the other port. You want full advance for more power while accelerating.
I hope I explained it ok, effective communication is not my forte.
Have you adjusted the floats yet? If so move on to the mixture screw. But remember they are idle mixtures and nothing more. Once you are off idle and driving its your floats and jetting you need to work on.
Has the motor backfired through the carb at all recently? How about blown power valve?
I hope I explained it ok, effective communication is not my forte.
Have you adjusted the floats yet? If so move on to the mixture screw. But remember they are idle mixtures and nothing more. Once you are off idle and driving its your floats and jetting you need to work on.
Has the motor backfired through the carb at all recently? How about blown power valve?
Last edited by 12secondstang; 01-21-2008 at 04:23 PM.
#12
Backfired a while back but I think that was with the old carb but could be wrong. might have been the new one. DO I need to hook the dist. up to the timing advance? yas or no. What should I do with the small manifold port? Plug it? The big one is hooked into the valve cover with an old pcv valve!
Should I pull a plug and look at it?
Should I pull a plug and look at it?
#13
I would say no not necessary. I never hooked my dist to a port on my mustang. I did however, time my car to 34 degrees total timing at 2500rpm. I never set my initial timing because without vacuum advance you would lose performance and power. As far as the ports on the carb. Just plug what you are not using. Leave your pcv the way you have it.
#15
You can but you will need to adjust your timing accordingly. After adjusting your timing at 2500 rpm, you will notice your base(idle) timing is upwards of 18° or higher. This may cause hard starting but it never did on my car. If it does you may need to hook up the vacuum advance and reset you base timing to 12°.
**we have gotten away from your real issue. A rich condition. You should really deal with that first. You don't to keep pushing fuel through the cylinders.
**we have gotten away from your real issue. A rich condition. You should really deal with that first. You don't to keep pushing fuel through the cylinders.