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Carburator Help

11-13-2007, 08:38 AM
My 86 sprint is running really rich, causing poor proformance. I dont know how to ajust the thing. Can anyone help?

11-13-2007, 01:57 PM
A carb problem in an 11 year old car is more likely something that has gotten stuck (like a choke butterfly) or clogged (like one of the air-bleeder jets in the cruise circuit), or split open (like the rubber bladder in the carburetor's accelerator pump) or that the float inside the float bowl has been taking on gas and letting the fuel level in the float chamber get too high. Depending on the carb it could be several other things; all of which are likely to happen eventually to an old carb.
For many such problems there is not an adjustment per se. You have to remove the carb and either get a rebuilt one, have yours rebuilt, or buy a kit and rebuild it yourself. And the cheapest rebuilt carb is not necessarily the best one!
Along with the carb rebuild you should think about replacing all of the rubber vacuum and fuel lines, the pcv valve, etc.
Carburetors dont last forever - without being rebuilt. They can go bad from high mileage, and they can go bad from sitting too much. You would want to replace the carburtor base gasket to forestall vacuum leaks. If the car has its original fuel pump, it would be a good idea to replace that; they wont last forever either. Naturally change the fuel filter along with the fuel pump. If the fuel lines from the tank to the pump and then to the carburetor are rubber tubing - then that rubber section should also be replaced after 11 years.
To get proper fuel mileage, you also need to ensure the vacuum advance mechanism in/on the distributor is working. If it fails the engine will run the same, but mpg will drop off a lot. If the centrifugal advance mechanism in the distributor is mechanical, and gets sticky - it will rob you of power, and can cause the plugs to get too dark (because of the ignition not being advanced at higher rpms).
And to know if you have bad valves (fairly common on small displacement engines), it would be a good idea to do a compression check). With some types of carburetors a leaky intake valve will mess up the fuel distribution a lot - resulting in poor gas mileage and dirty plugs.
You could price out rebuilt carbs at places like:
www.carburetorexchange.com, or www.rockauto.com.
Good Luck, I wish I had a car with such good mpg.

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