I am trying to adjust the carb on my 77 sedan with auto trans. It is a Holley 5200 that I got from eBay & it just doesn't seem to run right. I know the year is off by one, as I bought one for a 1976 but it's just not right. I swapped the electric choke from the old carb & tried to run the car. While the car starts right up & runs the fast idle is off bigtime.
If I adjust the screw at the back of the carb the curb idle raises but can't get the fast idle isn't right.
What on earth am I doing wrong?
If you look at the backside of the choke housing, you'll see a plastic cam (mine are green) and a screw that sets on the steps of the cam. The screw determines the idle speeds while the engine is reaching operating temp. The spring in the choke should open up the cam when the engine reaches temp. Make sure the "eye" of the spring goes over the linkage arm. It's easy to miss and can cause the problem you have. If the spring is on right, and the linkage tries to unload (goes to the bottom step of the cam) when warm, back off the fast idle screw.
Thanks for the tip. I took a look at the carb & that looks like it was the issue. I have run out of daylight, so I will continue to work on the issue the next time I work on the car.
OK, update time
I tried the adjustment & it has fixed the problem. I now will be adjusting the fast idle speed, then the curb idle speed.
The only thing that concerns me is this thing is a real dog. I dunno if it is the fact it is carbureted, or the carburetor was for a 76 instead of a 77, but it really is sluggish! What can I do to help that issue out?
Are your jets installed correctly? I have heard that drilling them our a couple sizes bigger makes a huge difference on a purely stock carb.
Well Dave, I think the jets are in right, as the carb was a rebuilt unit on ebay. It was still wrapped in plastic when I bought it. How much should they be drilled & where are they located?
I can't remember exactly how much larger they need to go, but if you remove the top of the carb, there will be two jets (primary and secondary) at the top of the float bowl next to each throttle bore, then you will have two jets (primary and secondary) in the bottom of the float bowl.
Searching the forums would bring up the correct info, but if you don't have time I'll look around tonight.
So wouldn't drilling make the engine run richer? I know the car doesn't seem the greatest on gas mileage to begin with, so I am concerned with that.
It would, but it has something to do with the gasoline grades of then vs. now, and it runs smoother/better with the extra fuel delivery.
check ignition timing
I drilled out the 132 jet to 147 for the secondary and placed the 142 into the primary . The motor revved out better. It worked.
Got the tin box of small drills from Harbor Freight and got my digital calipers out and a drill measured at 1.47 millimeter. Obviously I used this one.
132 means 1.32 millimeter on the earlier carb (5200) that is a metric measurement.
I am still playing with the timing. My motor doesn't have the tag that tells what the timing should be. Easy to rotate the distributor.
If i can find the engine #, wherever it may be then can someone tell me the year of it>. It's a custom car powered by a 2.3 Pinto motor.
Thanks in advance.