Runs rich, wants to clunk out under load

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garhett

Runs rich, wants to clunk out under load

Post by garhett »

I believe car has been running rich for a while, but not terrible. The other day it started acting up when I'd try to accelerate and now it wants to almost die if you step on it too much.

I'm not sure the two problems are related, but I've done everything I can to try and get the mixture right, but it only runs OK with mixture screw seated. Bought a carb kit and replaced float, needle and seat, and diaphragm. No difference.

New plugs, wires, cap, rotor, points, and even coil... squat :)

Car idles a little rough, but OK. Will drive OK at first but quickly starts to act up after driven for a few minutes.
Pressure tested fuel pump at idle and was at 4psi which seems normal, but couldn't drive with gauge (was rental and leaked)

I'm really leaning towards fuel pump as I just cant see what else would cause these symptons.
So Cal Mark

Re: Runs rich, wants to clunk out under load

Post by So Cal Mark »

if you're sure it's running rich, don't waste money on the pump. If it runs with the mixture screw seated, you're getting fuel through another circuit in the carb
garhett

Re: Runs rich, wants to clunk out under load

Post by garhett »

So Cal Mark wrote:If it runs with the mixture screw seated, you're getting fuel through another circuit in the carb
Would I be able to see from where? What would cause that?
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bradartigue
Posts: 2183
Joined: Thu Sep 20, 2007 2:35 pm
Your car is a: 1970 Sport Spider
Location: Atlanta, GA

Re: Runs rich, wants to clunk out under load

Post by bradartigue »

Running rich with the mixture screw all the way is most likely caused by the throttle linkage being adjusted incorrectly.

Do this:

There is always a chance that the carburetor is so filthy inside that it is doing weird things, so you could blast out all the jets with carburetor cleaner before you start doing this stuff.

Start the car and go for a drive to warm it up.
Stop the car, preferably in your driveway near your tools
Remove the air filter
Start the engine again.
Turn the idle stop out until the engine dies.

Did it die? It should have. Assuming it did, turn the idle mixture screw out (rich) one full rotation. Turn the idle stop in until it just contacts the throttle assembly, then turn it one more full turn. Start the motor. Use the idle mixture screw to achieve the highest possible idle speed without stumbling or bogging down. Then use the stop screw to increase (or decrease) the idle to 850 +/- 50 RPM.

Did it not die? If not then you may have an air leak in the carburetor base or vacuum hoses, you may have a broken mixture screw (how does the tip look?), and so on. Do those things above, report back.
So Cal Mark

Re: Runs rich, wants to clunk out under load

Post by So Cal Mark »

you could have a sinking float, misadjusted float, loose idle cutoff solenoid or worn idle jet besides the common misadjustments
garhett

Re: Runs rich, wants to clunk out under load

Post by garhett »

well hopefully someone will still check this thread, I know its been a while an I do apologize.

There has been some progress. I had checked the idle solenoid before and I did get a click when connecting the wire. So after learning how easy they clog I took it out and cleaned it. Didn't realize just how easy that was.

After putting it back it I decided to check that it was working again just to make sure since it's been a while since I checked it before. This time I got nothin out of it. Had my pops come over and he monkeyed with it a bit and turns out something is loose in the solenoid itself and if you put some pressure on the end where the wire connects the darn thing works all a sudden. :)

So we got it running again, made my adjustments and she has just about a perfect purr. :D So I decide to take it down the road and see if it drives well.... NOPE :( Still looses power and sounds like it back fires once I hit 2500 or I really push the peddle down.

The backfire sounds like it's under the hood, not the exhaust. Not sure if that helps. Also did check the plugs and they're covered in soot still. I believe our little hillbilly rig works and that there's pressure on the end of the solenoid, but I'm not positive it really works while driving or that the solenoid isn't simply shot.
I'm pretty sure I'm just gonna go ahead and order a new solenoid, was just looking for some feedback. Is this a typical symptom of a bad solenoid?

Here's a pic of our setup
Image
Sorry it's at a weird angle, tried fixing.
So Cal Mark

Re: Runs rich, wants to clunk out under load

Post by So Cal Mark »

very very common
garhett

Re: Runs rich, wants to clunk out under load

Post by garhett »

Great, thank you so much Mark.
Should have the part in a couple days, I'll report back then.
garhett

Re: Runs rich, wants to clunk out under load

Post by garhett »

Success!!!
Sure enough, popped the new solenoid in and w/ a few adjustments she's just purrrrring :D

Still had problems with the miss though... :?

Ran her for a bit, and noticed arcing from what looked like the dizzy to the valve cover :shock:

Popped the cap and swapped the wires around... seemed to work but once or twice now it did the same thing, just one quick miss though.

Very sure I can sort that out though. Again THANK YOU EVERYONE! THANK YOU THANK YOU THANK YOU!!!
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