New carb question or frustration taking over

[yodabiri]

Ok this is really frustrating! I swapped the loadomatic for a DUI and I tried it with my 1100 autolite, it worked fairly well. Then I got a Holley 7448 carb and I put that on, and it ran with some problems but ran and i got it to work fine. Then i discovered that the holley was leaking (used carb) so i got a nice shiny Demon 2bbl, and everything started to go downhill from there. I put the demon on and i got it to work but I thought the timing was off, so i messed around with the timing and fuel mixture until i completely screwed it up. Now it starts up when i prime the throttle, but does not keep on working unless it is at like 3000 rpm. When it drops below that it starts choking and dies. I am at wits end and I am gonna let a shop handle it from here on, but I thought there may be some suggestions from people that i can try. Does anybody have any thoughts on what may be wrong? (BTW i put the original 1100 back on an it fired up and ran and idled though at 2000rmp)

Thank you very much in advance!

 

[addo]

Start by setting the timing back where it should be. Check all your plugs for ideal gapping and possible sooting up.

If it won't run slowly, go off the DUI's ignition curve figure for correct mechanical advance at the lowest RPM you can achieve, for now. That will require you to cap the carb vacuum line while setting.

Isolate all vacuum draw from the carb or intake - such as trans kickdown, brake booster, distributor advance - cap them all for now and try running again.

Look for leaks created by overtightening of a carb or adapter, also sealant blown open by a backfire or fuel erosion. Be sure the choke is fully open - not just the flap, but the fast idle cam, too.

Note that Holleys are noted for some inconsistencies in manufacture, being at times less than ideal from new. What's to say the Demon may not be similarly impaired? Although, similar behaviour with two carbs leads most thoughts elsewhere.

A workshop when faced with a situation like yours is really only likely to apply a mixture of common sense, EGO readings, and vacuum results to diagnose. If you can stay out of there for now, it will be cheaper.

Regards, Adam

 

[yodabiri]

I figured that it would be much much cheaper, but i am too annoyed by it right now. Thats probably because i lack the proper tools like a timing light and a vacuum guage in order to determine what is going on. I will try and find all of the vacuum leaks and whatnot, and then see how it runs. I think that my gaps are set to the specified 0.055 of an inch, but i will try and set it a bit smaller. Oh yea i completely forgot to tell what car it is. It is a 65 mustang with a 3spd. I am just trying to get it running for now so that it doesnt sit around while i gather the parts to swap in a 250 with a t5 and an 8.8 rear end. I know its ambitious but i am taking it step by step and i am getting to know mechanics that people have recomended.

Thank you!

 

[addo]

For the cost of a mechanic's time, you can probably buy a vacuum gauge, compression tester and timing light. If you timed the DUI with no gauges at all, then you're probably way wrong on the base timing.

I don't trust all mechanics; there are as many horror stories about bad workshops as there are about instant oil change shops.

 

[yodabiri]

I know what you mean about the shops that you cant trust. I had some bad experiences. Actually i dont remember any good ones for that matter. I got the original 1100 to work very well yesterday with an idle at 600 with no missing and it definitely had better throttle response than what i remember from the last time i drove it. I will try the swap again and see what happens then.

I will check back with the progress.


Thank you!