DUI installed in 66 200 mustang, off idle bog question

[H555]

my son and I installed the performanc dist from Mike yesterday. very nice installation. this was after a rebuilt loado, then a pertronix then a points style from a 68 something. this is by far the best by a long shot. cleaned up the idle and most of the off idle bog. sprung for the live wires too (replaced a set of other brand hi perf wires). this is in a 66 200 mustang, with a C4. also put on the pony carbs 1101 a few months ago, 2" exhaust and turbo muffler. it runs well, needs a rebuild, maybe this winter if we get the Barracuda on the road. so the question... I've pushed the advance to the point that it just barely pings. hooked up to ported vac, seems to like that better. also gapped the plugs to .055 but i can't completely eliminate the off idle bog, it's slight but still there. should I reduce the plug gap? I'm reluctant to mess with the carb much because it was perfect when we put it on 2 months ago, that was with the later model points dizzy. thanks for the advice. Ron

 

[mach1 mark]

I put a DUI and the nice wires on my original 200 w/C4 and the 1100 carb. I got the same bog when I slammed the pedal to the floor. But If I just eased it to the floor let it get going, then I slammed it to the floor then it took right off. I had to set the timing to about 10btdc to stop pinging on load. Did you reset the fuel to air idle mixture? I also started with a plug gap of 55 and had to reduce it to about 50. I little race gas made a big difference also.

 

[CZLN6]

HOwdy H555 and all:

If the bog appeared after installing the DUI, and did not exist prior to, and the only things that changed are the distributor, timing and new wires, then recheck all timing settings, connections, vacuum leaks, etc....

IF the bog existed prior to the new distributor then I'd be inclined to reconsider carburetion- most likely the accelerator pump system. Especially since you said you've already maximized the initial adviace.

More initial timing and a stronger spark can help with an off idle bog, but not always be the complete answer. Where you said, "cleaned up the idle and most of the off idle bog" causes me to think the problem existed prior to installing the DUI. You also said that the carb was perfect 2 month ago. When did the bog start to appear? Any other symptoms or conditions?

How long since you've rebuilt the carb? Which hole do you have the accelerator pump pivot set at?

Adios, David

 

[mugsy]

I bought a Pony carb and had terrible problems with an off idle bog. Went back to my 1970 Motocraft replacement carb and all was good. Pony carbs are junk IMO. Anyway......

Sounds like the bog is carb related versus dizzy. Look into the carb throat and move the throttle. The accel pump should shoot fuel out immediately. Play with that first.

tanx,
Mugsy

 

[Anonymous]

I would try reducing the gap to around 0.045"

 

[H555]

thanks for the tips. The 1101 is brand new (or more accurately 3 months new). when we first got it and installed in it ran beautifully. that was with the loado dizzy and a pertronix II (that lasted a week). then I went to a non-loado points dizzy then this DUI. that's why I'm thinking it's ignition related. I e-mailed the folks at Pony carbs and will post what they suggest. i'm willing to just live with this till I do the engine rebuild. it's still way better than it was and 10 times when we bought it 18 months ago. it starts easily, even in cold wet weather, runs well other than this bog. thanks everyone.

 

[falcon fanatic]

sounds like it just gets a little lean right there. Not sure about my physics here, but better ignition could aggravate a lean situation by combusting more thoroughly? Thus, when you weakened the ignition by making the gap smaller things got better. Sounds like more fuel, not less ignition is the the solution.

 

[MLINE]

You mentioned the carb ran great with the load-o-matic dizzy. Could the bog be because it's a load-o-matic carb with the SCV?
I'm just throwing this out there as a suggestion.

Good luck.

 

[CZLN6]

Howdy All:

Good point Mike! The 1101s came both ways. It was 1st used in '63 on the full size Ford cars with a 223 six, with a SCV. The one used on the '69 250 Mustangs was NON-SCV.

Hey H555- Does your 1101 have a SCV? If so, it is not sending the correct vacuum signal to the vacuum advance on your new HEI.

THe devil is always in the details.

Adios, David