I have moved this from an other (maybe misleading) tread

I hope someone can help me with this problem:

Since my last posting in this forum my car has been repaired at a workshop. They repaired the brakes and steering +++.
They also repaired/changed the gasket between the intake manifold (Performer Rpm) and the engine.(Reason: small oil-leak)

Distributorcap, rotor, ignitionwires and sparkplugs was also changed with new parts to ensure proper ignition.

But the engine performance is now very bad. It starts rapid and ok, idling is ok. But when driving, it feels lazy, and when I push kickdown, it hestitates and "vibrates" (like 1 or 2 sylinders are off..?). And I observe dark/brown (not blue) exhaust, after this kickdown. I can smell fuel too. If I drive f.ex. in 2 gear (locked) and drive in 3000 rpm, and then push kickdown, it accellerate much better. The fuel consum is high. I havent measured exactly, but I think about 8 miles/gallon? While kickdown I sometimes also hear a "boff"(just like it had a lean mixture), but since I definitely belive it get too much fuel / too rich mixture, can such "boff" also appear with rich mixture??

I will also mention that if I held my hand rigth back at the end of exhaust-pipe, and someone rev up the engine a bit (warm engine), I get brown and wet-spotted exhaust at my hand. That cant be right?? (I havent catalytic converter or any other anti-pollution system)
I discovered that the carb hasn`t choke (was removed- chokehorn is cut off). Nevertheless, when the engine is cold it starts and drive rather OK without any choke! (as long as I avoid too much gaspedal)

So far I would belive that the carb(Holley) must be bad or misfunctioning, giving way too rich mixture. Someone also told me that this model carb was a cheap and a bad carb. Comments?

I contacted holley.com (with pic of carb) and they could tell me this:
"The carb is a model/serie 4010, and we stopped delivery/sale of this model in -98. It is originally a vacuum secondary, but someone has installed a mecanical secondary linkage on it. The chokehorn is cut off and we cannot identify what cfm it has "

I have read that this is a improper and bad solution to convert a carb like this. Link: http://www.bob2000.com/carb.htm (Read:How to switch from vacuum sec......)

BUT, can it be an another cause to this problem?
The workshop had to remove complete distributor when removing inlet manifold/gasket. When remounting the distributor they adjusted ignition timing correctly. But they wasnt 100% sure if the timing MARKS was stamped on engine was correct (if timingmark parts changed??)
Anyway, IF the ignition is too late/retard, can that alone cause these dramatic symptons??

I consider changing to a Edelbrock 600cfm serie 1405 carb (new?rebuilt?) to cure this. But I still have a problem if ignition is wrong.

I complained to the workshop about this. They checked comp. in engine, it was ok on all sylinders. They discovered also that spark plugs had carbon/wet, like rich mix.

I will also mention that when I bougth the car I filled the fuel-tank with this fuel: 95 octane Shell V-power. It has carb/engine-cleaning qualities. Could this caused carb to get "mad"...?? Link: http://www.sm.shell.no/Bilist/vpower.cfm

Comments / help / tips ??

 

Sounds like you're running rich to me based on everything you've described.... You SURE the carb is set properly? Seeing as how your carb has already been screwed with, I'd say it might be a good investment just to get a new one like you described, so at least you'll KNOW you have a carb that is working properly and hasn't been shall we say backwoods modified...

Bad ignition timing is a possibility, but it still sounds rich to me. It's possible though that your ignition timing is a little bit retarded. However if you want to test it, you can set your timing the hillbilly way! Hit it with the light, then slowly advance the timing with the engine at an idle. Don't pay attention to the amount of degrees it actually says, since you said they may be wrong, but pay attention to the tick marks....sort of use them as reference points. Keep SLOWLY advancing it until you can hear it start to ping/detonate...once you hit that point, retard it 2 or 3 degrees back. Then take it out for a drive and listen for detonation. If it's there it will be most prevalent at low rpms in high gears under heavy load. If you have an automatic, get on the highway or on a long stretched road...get it into 4th gear, and give it as much gas as you can without hitting the kickdown to put it back into 3rd. If it's going to ping, it will most likely do it there. Then if it does, retard it another 1-2 degrees, and repeat until it goes away.

As far as the gas.....I doubt it had any effect at all. Manufacturers of gas have been saying for years that they put special additives in the gas...like Chevron's Techron gas, etc... Yes, they do put additives in it....but it's in such small amounts that I doubt it would have any real effect. They're not going to make it as strong as, say, a bottle of injector cleaner. Because you're not supposed to run injector cleaner ALL THE TIME, it's bad for the o-rings... Oh, well wait, STP has that commercial with Richard Petty saying to use a bottle every oil change right? Well if Richard Petty says it, it might be right! Any injector cleaner weak enough to be used that regularly is more like preventative maintenance and I wouldn't trust it do actually do much good to a problem that's already developed!

 

Many thanks for comments and tips

But if I buy a Edelbrock before touching ignition, and this Edelbrock needs tuning (more drastic than idling speed and idle-mix)? Then I have to deal with both problems, yeah?

The distributor was taken from a 350 engine. It has a mechanical centrifugal advance, and a vacuum unit (no ECM control there)

The workshop say they adjusted ignition timing at 4500 rpm (he explained why 4500.....) ....but I consider him as an expert at this, his own car is a TransAm GTA -86 with a 540cid....his local speed record at our bad, small roads in Norway is 205 mph (330 km/t) Next year he travels to Salt Lake desert with this car when he has tuned at least 2000 hp in it.

Agree then that I try first ignition timing adjustment hillbilly-way, if no improvement I turn back ignition exactly at the point where it was? And then buy a new carb.......??

I have a new, better pic of my carb (pic taken before changing ignition parts ang engine outside cleaning/steaming):

 

After a total evaluation I bougth a new Edelbrock Performer 600 cfm (1405) carb and I switched out the Holley.

But the sympton was exactly the same!!! Ahhh....wasted money..? And I have a probably well-function Holley in my hands (but empty for money!)

Then it HAS to be the ignition timing. Me and a mechanic I know (he said to me before I changed the carb that he was sure the ignition timing was wrong) shall turn the ignition wayyy forward. The workshop have also set the ignition incorrect.

When I`m thinking logic, the ignition/distributor is the only thing that was messed with, before/after the car was OK/not OK.

I `ll be back !

 

Maybe he was trying to set your total timing at 4500 rpms or whatever it is....I imagine at that level, that's going to be at full advance. But who knows exactly what he did. I'd do exactly what ya said you're going to do...try it the hillbilly way. I'm betting he didn't give it enough advance.

 

Thanks

But before turning the distributor to adjust ignition-timing:

In what direction do I turn it to move the ignition forward/earlier ignition? Counterclockwise or clockwise? And is the direction common on all chevy-engines?