Update on my '65

[Mercury Mike]

So I verified top dead center. The mark on my balancer was dead on. I dropped the dizzy in with rotor towards #1, slid it in perfectly, tightened it down. She fired right up! I set the timing to 12* with the vaccum disconnected and plugged. Plugged the vaccum in, and BOY does it work good! But....... no matter what I do to my idle screws, nothing changes. Is it possible that my carburetor is just totally shot, and that my ignition system is right where I want it to be? I mean, she is revving up perfectly, running like a top, it is so beautiful. Music to my ears.

There's a ticking noise now... I haven't quite found it, but it's not in the valvetrain. I used a long extension and listened and couldn't pinpoint it anywhere really, but it sounded fine inside the valve train.

The problem I'm facing now as well is that in park it idles like a sewing machine, but in Reverse of Drive, it stumbles, jumps around, as soon as I let off the brakes, she tries to get out from under me. However, when I hit the gas, it's like I'm not giving her gas at all, and she stumbles more. What could my problem be? Shot carb or...?

 

[ludwig]

Make sure your choke is coming off. It could be pinned shut and blocking the transition to warm operation at decent lower idle. A closed choke would give you a high idle and no power in drive. Depending on where you are in SoCal, you may not even need a choke, so pin it open and see if it runs that way. Once it warms up, you have plenty of time to fool with all the other stuff.
Set your warm idle in Drive not Park at about 750.

 

[Mercury Mike]

Alright. So I set my base idle to 12* with the vaccum plugged, and when I plugged in the vaccum line, in park, the RPM really shot up. Is it supposed to do that in park? I mean it really shot up. Since I live in a really nice part of CA, I always leave my choke open. Never had a need for it. What's with my idle screws not working, though? Any thoughts on that?

 

[ludwig]

What carb are you running?

Sounds like you have something hanging up someplace. Make sure all the levers and pull offs work. Throttle could be stuck open. Have you tried carb cleaner all over the thing while it is running? Make sure the throttle linkage is not resting where the throttle plate is too far open and the idle screws never even reach the seats. There is an adjuster rod from the throttle link to the throttle lever which can be too long and pushing it up. Try disconnecting the throttle bar and see if it settles down.
Did it work okay before and what did you change? Maybe start from there. I'm just working through the external stuff. Some of the other guys are privvy to the secret knowledge of the inside.

 

[ludwig]

I just read your other post. Maybe something is not moving down inside the carb, like a throttle plate is open or closed or there one of the adjusters came loose. Just a thought.
Personally, I keep an extra carb around just like the one on the car. I ended up studying it really carefully. I have not had a lick of trouble with the Pony 1100. It fired up right out of the box. I'm sure there are other good ones out there. Get another from the junk yard and rebuild it. Then you can rattle between the two and see what works better.

 

[Mercury Mike]

That sounds like a plan. Problem with CA is everyone buys mustangs from the yards as full cars, and they are never there for parts! I will see what I can do, I'd like a newly remanned carb, so that I can mess with it, but know that it's all there, with warranty. =)

 

[mugsy]

Do you have a vacuum gauge? if so, see how much vacuum is going to the dizzy at idle. With an OEM set-up there should be zero vacuum at the dizzy at idle. It sounds to me that the throttle blade is too far open and that is doing two things: first is that it is exposing vacuum to the
"ported" vacuum hole/slot inside the carb throat, and second, fuel is being sucked from both the idle by-pass port and the tranfer slot (that is why the idle mixture screw is not having any effect; too much fuel through the transfer slot).

To set the idle on a carb you can do that either with max vacuum or max RPM method. You'll need the vac gauge to set it up max vacuum and a tach for max rpm. Regardless of either way, it is an iterative process i.e. set the speed via the throttle stop, then set the idle mixture (which will more than likely change the speed), so the go back and set the idle speed, than then adjust the mixture again, etc, etc.. (personally I go back and forth 3-4 times and call it good).

 

[ludwig]

It sounds to me that the throttle blade is too far open

THat's exactly what I was thinking but couldn't say it so clearly.

 

[Anonymous]

My first thought is that you are using manifold vac for timing (increase in rpm) and ported vac for PCV(ticking noise). The PCV should go to the manifold itself and the vac advance to the ported source on the carb. Have no way of knowing but the symptoms sound likely. Best case senario and easiest fix and easiest to check.
As was said vac to dizzy should be zero at idle. Also sounds like a seriously malfunctioning vac adv. mechinism. Do you have a dual vac dizzy?
Another possible problem area is the modulator, on some models tranny fluid can be sucked into intake-or vac line is broke, another possible explanation of mix screws having no effect.- Does the modulator work off vac?
The good idle but falling on it's face under load can be --advance mech, Clogged carb jets, vac leak.

 

[Mercury Mike]

Single vac on dizzy, loadomatic. The vacuum comes from carb to dizzy. I will check to make sure that the throttle blade isn't open. I'll bet that's it though. I'll have some time tomorrow to pull the carb again. I will also check for vacuum leaks again. Thanks guys!

 

[mugsy]

As for the ticking noise... some times an exhaust leak will sound just like a lifter tick. I typically use just my hand and place CLOSE, but do not touch (for obvious reasons) at the joints. I've had good luck finding leaks that way. I try to find the laks right after the car has started... just in case you should so happen to touch an exhaust pipe.

As for the stumble, I had a similar problem when the initial or base timing was set too high on my '65. She would stall about 1/4 of the time starting from a stop. I used the timing procedure recomended by Pony Carbs, and it had the dizzy at about 30* at idle. Not good.

As far as I know the LOM carb should not have any vacuum going to the dizzy at idle. If you do find/measure vac there it is not correct. Sounds like the carb is way out of wack actually; and the open throttle blades are trying to cover for other issues.

Good Luck,
Mugsy 8)