rough running bbc
 

bbc starts easy but step on it stalls out slowly step on it goes runs rough up 2000 rpm and then kind of smooths out new fuel filters kind of gassy smell sometimes no vaccumun leaks checked with carb cleaner any ideas? timing set at 6 btdc.

Re: rough running bbc
 

Heavy float in the carb, crossed plug wires?

Re: rough running bbc
 

What carb?

And at least double your timing to 12 degrees. That’ll make it run better.

And what ‘isle’ do you live on?

Re: rough running bbc
 

Quadrajet I thought timing was 4 dtdc moved to 6 is't 12 a little much? other reply said heavy float?

Re: rough running bbc
 

Isle,Minnesota

Re: rough running bbc
 

I run-a minimum of 14 in everything.
I’ve had sbc that liked 22 initial and an L-88 427 that ran 26 initial.
Whenever you advance timing listen for pinging.

Re: rough running bbc
 

This test is easier if you have a tach hooked up to the engine that you can look at during testing. You can do it by ear, but it's harder.

With the engine running, disconnect one plug at a time. I don't know your level of expertise, so I am going to caution you to be careful and use insulated pliers if you can to keep from coming in contact with high voltage in the ignition circuit You should hear engine speed drop slightly. If it doesn't, you may have a bad plug, bad wire, or bad distributor cap causing a crossfire or an internal short to grond. A misfire would cause a gassy smell at the exhaust.

You can do a simple cylinder balance test by disconnecting the two wires that fire on alternative engine revolutions, but I don't know what your firing order is to tell you. That would definitely tell you that one of the two plugs MAY not be doing their job.

The next step is do a compression test on the weak cylinder. You want to rule out a burned exhaust valve. In that case, it wouldn't matter if the plugs are working or not. That would also give you the symptoms you are describing here.

I guess you have something to do on a Saturday afternoon, now.

Re: rough running bbc
 

[QUOTE=kazoocruiser; , but I don't know what your firing order is to tell you. That would definitely tell you that one of the two plugs MAY not be doing their job.

.[/QUOTE]

What is this!
You don't know The firing order.
Say it’s not so!

Re: rough running bbc
 

If he has a stock manifold on it, it's right in front of him. Maybe if he holds his truck up to the Internet with the hood open, I can see it to tell him.

If its any consolation, I don't know the firing order for a Jaguar V12, either.

I'm a mechanic, not a magician.

1978 Kawasaki 650SR 1243.
1986 Mazda B2200 1342

I owned those, so I had to know.:waah::ele:

Re: rough running bbc
 

Just jerkin’ your chain!
Maybe you got something to do now on a Saturday afternoon.
Googling Chevy firing orders!

Re: rough running bbc
 

A heavy float can cause the carburetor to run too rich by letting too much fuel into the bowl. Partial flooding. Another thing---Choke pull off not cracking the valve open upon initial start? 6 degrees of timing is not too much for a big block, last thing you want is it pinging. I've got mine at 6 and it occasionally pings if I've got something heavy in it and pulling the hill on the freeway.

Re: rough running bbc
 

Hey geezer#99 I guess you could have done that for me and the guy that might need it in the time it took to write your response. I didn't and there isn't any point to me filling my time with useless Google search for information.

I'm ASE certified, and the very last thing I need to do is learn information that isn't relevant to me or the problems I am getting paid to repair.

Please go and rattle your chains elsewhere.

Re: rough running bbc
 

ASE certified? Don't know the firing order of SBC/BBC? This is a Chevy forum. Your jerking our chain, right?

Re: rough running bbc
 

I see yet another flame starter. Instead of offering anything to the one who is having trouble with his engine situation in here, you and geezer#99 criticize someone who does.

Like geezer#99, in the time you took to respond to my posts, you could have gone to the web and placed that information in the forum. Not that it is needed. It just would have been a better time investment.

I don't have to know a firing order, as if it is some sort of tantric mantra. If I was a newbie with an old truck, would you be critical because I didn't "know the firing order of SBC/BBC? This is a Chevy forum."

My own truck has a I-6, so why is knowing a V8 firing order important for me to know? Thank you for your warm welcome to the forum.

I see you trolls haven't found fault with the diagnostic ideas I passed along. I also see neither of you have offered any of your own.

Just to make it simple for hillguy, once he figures out which terminal on his distributor is #1, the tower directly across from it on the opposite side of the cap will be the part of the crankshaft that carries the alternative fire cylinder. To do the simple balance test like I suggested he do doesn't even require starting with cylinder #1.

With the engine running, he could pull two wires on either side of the cap, plug them back in, and then go either clockwise or counterclockwise, pulling two wires at a time. NO FIRING ORDER KNOWLEDGE NEEDED.

This is seat of the pants diagnostics. You find a weak cylinder, if any, pull the plug and do a compression test.

Re: rough running bbc
 

Could be a number of things. We do not know the condition of the engine. Hard to diagnose engine troubles over the internet.
Based on the limited information provided, a couple of things I would start off checking, Is the vacuum advance on the distributor functioning? Set initial timing to 12º BTDC with engine at low idle and vacuum advance disconnected.

Re: rough running bbc
 

A a couple of you have nothing better to do then blow smoke