This is a 1985 Bronco I bought new. It has served me very well. I have had repairs done by others and as it got older, only asked that they do what was needed to make it run well. In the last few years it has rarely been on any roads and has moved trailers and plowed lots of snow. This winter it started to run rich and now runs terribly. When looking down the carb throat (using a mirror to avoid risk), gas is pouring in. On exam, the throttle position sensor and the choke are the only wires that remain attached, feedback solenoid is disconnected as is the solenoid on the vent line to the charcoal canister. These were tucked away and likely have been since the cat converter was removed some years ago. It ran fine that way till now(but was likely never over 40 mph so would not have noticed if spark advance didn't work). In the past, I would have thought bad float but with this carb, are there other likely problems? What would happen if I just got a carb for 83 or prior and left the current electrical in place? Our local junkyard still has three feet of snow so looking for a Duraspark won't happen for a while. I'm reluctant to put work into this carb as I don't think I'll use it in the future. The Bronco is no longer roadworthy so if it is going to be fixed, I'll be doing it and hoping to use it for years to come as the need to move snow remains pretty much guaranteed here. I'll look forward to any suggestions and help you can give me. Thanks

 

Sno - You didn't say what carb is on it, but I'll assume it is the original Carter 1bbl. Here's what typically causes a carb to go rich:

• Choke stuck: You didn't say when you looked down the carb if the choke was on or not, but if it isn't standing straight up when the engine is warm you have a problem.
• Sunk float: Sometimes the float goes bad, either springing a leak if it is brass or absorbing gas if it is plastic.
• Needle: The needle and seat combo controls the amount of gas getting into the carb, but if a piece of grit sticks to the soft material on the tip of the needle it can't shut the flow off and flooding or at least running rich results.
• Power valve: Another problem for some carbs is a blown power valve, but Carter didn't use them so if your carb is the original or direct replacement this won't be the problem.

Since you have wires disconnected it sounds like your computer is either disconnected or has its knickers in a twist. If disconnected you can put a carb on that doesn't have the controls on it. In fact, if you don't mind the way it was running before it went rich you can just ignore the computer if it is throwing codes.

 

Sno,

Welcome to the forum!

To add to what Gary said, your 1985 was originally equipped with what is refered to as a feedback system. The carburetor and distributor are controlled by the computer which gets input from several sensors. If anything is tampered with [and yours has been!], then the computer goes to a "limp home" or "safe" default. The timing is frozen @ ~10 BTDC and the carburetor goes to a rich mode... not good for mileage or performance.

It sounds like your original type of carburetor is still there since you mentioned the throttle position sensor has been disabled. You did mention that it ran fine like this until recently, so it must be something that has recently happened.

Does the choke still have the electrical wire attached? You should be able to measure ~7 volts there only while the engine is running. What about the 1/4" metal tube which goes from the exhaust manifold to the choke housing... it has a white insulating covering. Is it still attached?

Perhaps the float is stuck. Try tapping the carburetor bowl with the handle of a screwdriver while running and see if it makes a difference.

Have you checked for vacuum leaks? Look at all vacuum lines and also check that the carburetor is snug on the manifold. The two nuts holding the carburetor are known to vibrate loose as well as the screws holding the top and bottom of the carburetor together. To get to those, you have to remove the carburetor.

You might want to use the "search" feature of the forum and read about Duraspark conversion. Since so much has been modified, you might want to go that route before putting money into rebuilding your current carburetor.

Emmissions are important... apparantly, you do not live where this is enforced, base on your statement of having a disabled system for several years.

Good luck!

 

IIRC there are three decent threads in the sticky about DSII swaps.

 

I thank you for the help. I took the carb off and it does look like the float has been sinking. I reviewed the threads on Duraspark and it would seem to me that I should make that switch my game plan. It is snowing again and it is not likely I can do any scrounging any time soon. To get going, it seems I should buy a rebuilt carb 1983 or earlier and put that on. Then I can take the time later to look for a wiring harness,distributor,etc. Is there a problem with that plan that I don't see? What is the best year carb to get? Again thank you ever so much.

 

I don't know what the differences are between the years for those carbs, but I'd look for one w/o electrical connections other than the choke. But, if you were happy with the way it ran before this problem cropped up then your plan is workable. It'll get you back where you were and buy you time to do the DS-II swap, which will help the way it runs overall.

 

I did get a 1980 carb and it runs very nicely. I hope to switch the rest once I can get the parts so I get some spark advance. I have to say a great big thank you to you for the responses and all the work that went into organizing the prior posts so I could find the ones I needed. Thanks again!!

 

Congrats! Glad you got it going.