Rebuilt my 2100 carb this weekend- no more heat soak or flooding. Installed new points, condenser, rotor and plugs. Every thing set to factory specs except timing-have it set 10-12 btdc.
Engine idles good and accelerates good but runs rough at an idle or constant speed, i have glass packs so you can hear and feel the roughness.
Iv'e tried advancing and retarding timing, tried setting points from 17 to 22, adjust carb air but nothing seems to help.
Did not change plug wires or dist cap.
Does this sound like a fuel or fire problem What am i missing
Last edited by peanutman on Tue Feb 10, 2009 12:56 pm, edited 2 times in total.
Did you adjust idle jet screws at front of carb I adjusted mine for best idle vacuum which is 16-17 inches on my 302 also my truck seems to like an advance with the points dizzy at factory spec of 6 degrees tryed 8-10 and was very boggy little or no pickup.Just hook up a vacuum gauge to the hose for vacuum advance since you will want this unplugged anyways to set timing.Vacuum gauges are a good investment and can tell you much about the condition of you engine as well will detect a miss or valve train issues as well and most carb manufacturers tell you to adjust idle crews for max vacuum.
Lon
71 F100 302 T89OD
90 Mitsubishi Montero SWB
94 Tbird Sport 4.6L
86 F250 Super Cab S/D 351W H/O C6
01 Mitsu Montero Sport
boatcarpenter wrote:Did you adjust idle jet screws at front of carb I adjusted mine for best idle vacuum which is 16-17 inches on my 302 also my truck seems to like an advance with the points dizzy at factory spec of 6 degrees tryed 8-10 and was very boggy little or no pickup.Just hook up a vacuum gauge to the hose for vacuum advance since you will want this unplugged anyways to set timing.Vacuum gauges are a good investment and can tell you much about the condition of you engine as well will detect a miss or valve train issues as well and most carb manufacturers tell you to adjust idle crews for max vacuum.
Have not tried vac gauges. Adjusted air screws at front of carb out from closed 1.5 turns as carb kit recommended. Engine has lots of pep, just can't figure this roughness out. Runs great when accelerates can tell the roughness when you level out on gas or at idle, but yes tried several air settings.
Hows your float level with engine running?I rebuilt mine as well last weekend and it is running very rich as the plugs that I pulled today are showing.Instructions on the Sorenson kit I used said level should also be checked with engine running(which im a little scared of taking top of carb off while running next to my new 55,000 volt HEI coil)but I will have to check it out with fire extinguisher in hand.I notice that there is gas seepage out of carbs top gasket when running.WIsh the Autolites had a sight glass...maybe a future mod GL with your project peanutman
Lon
71 F100 302 T89OD
90 Mitsubishi Montero SWB
94 Tbird Sport 4.6L
86 F250 Super Cab S/D 351W H/O C6
01 Mitsu Montero Sport
I used the same kit.I Set the float level dry. I don;t think thats my problem but may have to look at wet adjustment if i can't figure this out. I keep leaning toward a vacuum leak. Won't have time to mess with it till next weekend.
Just trying to get some pointers until then, Thanks!
fordman wrote:thinking of vacuum leaks. you did put a new carb ase gasket on the intake didnt you?
Yes new gaskets above and below the spacer. Oh and by the way the heat soak problem is back
Gonna tear everything back down this weekend and see if i missed something.
Not gettin the suggestions i thought i would. Fuel, fire ,but thanks boatcarpenter and fordman for your input. I'm just a shadetree mech so i guess i'll get the books and testers out and start tracing the problem down. Gonna cap off all the vac ports and start from there with a can of wd-40 and look for vac leaks. Since it wasn't running this bad before i done all this i don't think i have a valve problem.
fordman wrote:thinking of vacuum leaks. you did put a new carb ase gasket on the intake didnt you?
Fordman i do have aquestion for you. Several of my vac lines run back to a plastic blue valve on the back of the intake, do you know what that is Not finding ant info on it in my books or part mags.
usually that tee is metal some like the pic . the dist should be hooked directly to the bottom of the carb. can you post a pic of what you have? the first pic is of a 1978 302 vacuum t the second came off of a 69 FE.
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fordman wrote:usually that tee is metal some like the pic . the dist should be hooked directly to the bottom of the carb. can you post a pic of what you have? the first pic is of a 1978 302 vacuum t the second came off of a 69 FE.
Don't have a pic at this time but found one at macs, they are calling it a vacuum spark advance control. I have a dual port vac advance on the dizzy, on hose goes to carb and the other to this control valve. Book explains one port is for low end vac and the other is high end vac.
fordman wrote:usually that tee is metal some like the pic . the dist should be hooked directly to the bottom of the carb. can you post a pic of what you have? the first pic is of a 1978 302 vacuum t the second came off of a 69 FE.
Don't have a pic at this time but found one at macs, they are calling it a vacuum spark advance control. I have a dual port vac advance on the dizzy, on hose goes to carb and the other to this control valve. Book explains one port is for low end vac and the other is high end vac.
Correction fordman the valve im talking about is the egr according to my chilton manual, bolts to the back of the intake on a 302.
george worley wrote:If the EGR valve is not working right it will idle rough and act like a burnt valve. May need to clean the carbon out of it.
Thanks for that info gw. From what i am reading in the chilton manual i have a vacuum controlled egr valve. I think thats what the little blue valve at the back of my intake is. Several vac hoses run to it including one of the two vac hoses coming from my dizzy.
1.5 on a jet is a guideline if all is in order...moving them a bit is ok....but anymore and you are compensating for something else....move em a little see if she smooths out
Looks like i found the problem. The valve at the back of the intake is some kind of vac advance adjustment. It has a screw under the cover, when i remove the vac advance hose on the dizzy the engine levels out but i loose some of my timing advance. My dizzy has two ports. Will post pics tomorrow. I suspect when i rebuilt the carb and done tune up it needs re -adjusting.
Iv'e PMed hawk for instructions on what this valve is and proper adjustment or test it or vac advance to see if one or the other is bad. Will keep yall posted or if someone else can help i would appreciate it.
Robbie
What am i missing 
GL with your project peanutman
