to rebuild or not to rebuild

[chaka]

That is the question!

I have a 1980 FJ40 Chevy 250 I6 with a carb Rochester 7040021 (1970-ish monojet) that won't pass emissions. I guess i have three choices....

1. Rebuild original carb (although no choke on original)
2. Acquire a new (rebuilt carb), send the core of the old one back. (suggestions on which carb are appreciated,)
3. Don't do anything and run rich - (I only would have to pass emissions if i get inspected in the next 4 months, in 2005 i will be exempt from emissions)

do i risk damage if i run rich? also, what is a good carb to switch to? hopfully looking for something that will bolt on...

also - about how long will a rebuild take for a newbie?


advice?

chaka

 

[Romer]

I am not familure with your carb, but I would think there is an idle mixture screw to adjust it so its not so rich. Are there other reasons why you think you need a rebuild? Why do you think it's the carb that is keeping you from pasiing?

 

[chaka]

I took it for an emissions inspection - they said it was running too rich. I tried to lean out the mixture (actually had a mechanic friend help out) and he said it was leaned out almost as much as possible.... is that possible? leaned out as much as possible and still running too rich?

i'm new at all this so forgive me for the dumb questions....

 

[Dave E]

I know the timing can affect emissions as well. I've seen a mechanic adjust the timing out of spec. It put the emissions in spec. And it only has to last for the test. But he was using an emissions tester to adjust the timing.

Dave

 

[nailbender]

You can only adjust the mix at idle with the screw. Inspections usually are at two differant speeds and you have to pass both. You need to change the jets to change the mixture above idle speed. A new air filter before the test is a good idea. Make sure the choke is working right also. If it still won't pass have your mechanic friend watch over your sholder while you rebuild it.