The Stovebolt Site Forums The Shop Area Engine Shop Carb Conundrum - 58 - 235

Despite doing a full tune-up and carb tune-up my truck failed Aircare again with simular readings on CO2. The CO2 was 9 for both idle and running when it shouldn't be past 4.5 - it's rich. One fellow said the nozzle for the gas inside is too large and letting in too much gas. I have no clue what to do now. Now that my truck is officially rejected and uninsurable I can always remove the carb but don't know what to do with it. I'd appreciate any guidance in how to deal with this issue. I had one quote over the phone for $260 to refurbish the carb but I thought it was a bit high. Thanks.

Mag,

Plenty of kits are available for rebuilding your carb, and quite frankly, its not rocket science, and in fact can be an enjoyable bit of work. These kits will include new jets and all gaskets, etc. That, of course, presumes there is nothing structurally wrong with the carb (check for warping) or some previous owner has not "modified" it in some fashion.

$260 US or Canadian would appear to be very high if this is a 235. Plenty of rebuilts are available if you do not want to tackle the job for approximately $120 USD from Chevy Duty and such other suppliers. For local sources, contact red58 as he is in your neighborhood. I have found him to be an invaluable source of information.

Richard

if it is a rochester B I would bet money the power piston is sticking, I finally polished mine w/fine steel wool to get it to work properly-I got 18.5 mpg keeping it @60 or below. started @12.5 mpg. carb are simple & a repair kit here runs about $13. An HEI will also help emissions/MPG. I still can't believe they smog a '58, I mean it came with NO emission controls, they weren't even avaliable. brian

geez that's a drag! 260 is definitely too much, check at NAPA or Lordco, they should be able to get you a rebuilt for way less, should be the same 55-62 - it might be that it needs a smaller jet - might try higher heat range plugs too

Bill

i bought one for a 61 235 at autozone for around 100? dollars.

They have a smog check for a vehicle with no smog controls that never had smog controls? In this country we'd call that crazy (and literally unconstitutional as it would be classified as an ex post facto law). Second, how do you have high CO2 readings? Do you mean high CO readings (incomplete combustion) or high hydrocarbon readings (really incomplete combustion)? CO2 is the final product in the combustion process. Its production constitutes complete combustion of the fuel introduced into the combustion chambers. If the only thing coming out of your truck's tailpipe is CO2, you can't have a better tuned engine.

it's not a "smog check" Lumbergh, it an emissions test [and is CO] - any vehicle has limits based on it's original configuration, not unreasonable to insist that any vehicle not be adding more crap to the air than necessary - and as far as constitionality, your supreme court is about to decide that question !!

Bill

I guess I should have removed the PCV setup as you recommended earlier, Bill. I'm thinking it's affecting the exhaust. You said an electrical box plug should work to plug the valve cover end I think.

The carb kit we used didn't have replacement jets so that's what I'm going to hit. The truck has always run rich no matter what adjustments were done. If this doesn't work I'll try and find another carb. So I'm lookin' for "jets" - didn't know the name of them.

Thanks Guys!

Mike - that "pcv" setup isn't helping anything for sure - if you've get the manifold hole properly plugged, you're better off as it hasta be lowering the vacuum which isn't gonna make it better - also if you have a shop manual there's some info there on the minimal pcv arrangement they had - see pg 6-15 [I think it was only normally used on the 283]

I'll see if buddy Bruce has any thoughts on what might work for ya, he's a certified inspector

Bill