Strange accel problem

[Mercury Mike]

{1965 Mustang} Alright, so I got really tired of the hesitation in my autolite 1100. I look over everything, hit the throttle at the carb and it is great. No hesitation. The throttle opened completely, sounded real great. Still some thump thump thump that I haven't quite gotten figured out. So I pulled on the kickdown arm to get the acceleration from that point, and BAM, I found the problem: The kickdown linkage to the tranny wasn't hardly letting the carb open up at all. It was opening about a third of the way, then the kickdown was actually pulling the arm back towards the tranny, regardless of where the pedal was, and letting the throttle close, then opening another third of the way. I readjusted the float, checked the acceleration pump, checked weights and balls. Everything checked out inside the carb. I pulled the linkage off of the kickdown, made sure the timing was dead 10* (too much or...?). When I pulled the kickdown linkage, and tightened the arm (the two 7/16 bolts on the arm) so that it wouldn't move anymore. When it's in park, it revs up great, sounds like a beast. Goes thump thump thump if I continuously rev it, but if I give it a quick shot it sounds great. Still no leads on the thump though if anyone's experienced that before. I'm not missing at any of my cylinders, getting good spark to all of them. It idles great, starts right up. When I put it in reverse, it was fine accelerating backwards. When I put it in drive, I hit the gas, and she stumbled and died. I backed it back into my spot, and went out for lunch.

I got three questions:

1. Why is it stumbling in drive now? Could I have taken the float out of adjustment or something?

2. My kickdown linkage isn't long enough to reach wide open throttle... How do I elongate it? Am I doing something wrong? Disconnecting the spring down near the neutral safety switch, pulling the cable out as far as it can go, and trying to match it up to the full pull of the kick down arm.

3. If I can't make the linkage longer, besides not being able to downshift by kickdown method, is there any other disadvantage to having the kickdown linkage disconnected completely?

Thanks guys.

 

[mkgcars]

1. Why is it stumbling in drive now? Could I have taken the float out of adjustment or something?

2. My kickdown linkage isn't long enough to reach wide open throttle... How do I elongate it? Am I doing something wrong? Disconnecting the spring down near the neutral safety switch, pulling the cable out as far as it can go, and trying to match it up to the full pull of the kick down arm.

3. If I can't make the linkage longer, besides not being able to downshift by kickdown method, is there any other disadvantage to having the kickdown linkage disconnected completely?

I don't think #1 is relative to #2.
- whats it idle at in park? Bump it up to 650 and see what happens.
- is the vacuum hose from the intake to the tranny okay?
- the accel pump is set so that just as you get on the gas the accel pump rod starts to move?
- does the carb have the anti-stall dashpot? This should also be backing off as you get on the gas. If it's not then perhaps it's getting too much gas initially (when both the accel pump shot and the anti-stall is kicked in).
- try the timing at 13 for a test.
- know what size jet you're running? It may be too small.

#2. The linkage should have some free play at the top - it's not stuck is it? Free it up if it is.
To see whether this is really related to #1 try disconnecting it.

#3 You don't want to be without downshifting.

Keep us posted on results.
Good luck.
matt

PS:

Personally I resolved all of my driveability issues with my 1100 by
1. Running a larger jet. Had a 54 in 1 carb and a 59 in another. First I went with a 64 and then a 67. Too small is no good. I'd say try at least a 64 (which ran well in my '65 200).
2. Setting the accel pump so it kicked it when the throttle moved (rather than using the drill bit gap method to set it).
3. Having a fuel pump that didn't put out too much pressure.
4. Advancing the timing a few degrees (long story here, car was manual has manual #'d dizzy and so originally was running timing too low).

 

[Anonymous]

What exactly is "thump, thump, thump?"

Are you losing a rod bearing?

Or are you describing the engine lugging?

cheers,
Steve-O

 

[Mercury Mike]

I hope I'm not losing a rod bearing. If I am I know a certain engine building shop that's getting a call! It's a rebuilt 200. It goes like vroooom, then it starts shaking like thump thump thump thump. It actually sounds like a thump. I will take a small video of it and then you guys can see.

Alright, so here's the latest. It starts great, gets GREAT throttle now with the kickdown disconnected, but I can't slow it down at idle. The idle screws were working fine, then I hit the throttle, and it sped up and wouldn't slow down. It's running wayyyy too fast at idle now, but the throttle response is awesome. I'm stumped... again.

When I rebuilt the tranny about 6 months ago, I changed the hose to the modulator. Shifts great. The kickdown cable just doesn't reach the arm at full throttle. It's weird. I can probably rig it up to fit worst case, but I am stumped as to why it doesn't fit. The kickdown works great, too, when it's connected. I will get a few pictures and then post in order what was happening and what's happening now. I have a full day to do that tomorrow so I shouldn't have an issue. I will bump the timing a bit.

 

[Mercury Mike]

UPDATE:

Went outside to check the timing just for fun. The timing was WAY off, but the distributor was in the same place. I set it back to 12* with my light. The idle screws adjusted the idle again, but it wouldn't slow down hardly at all, and started backfiring like crazy out the exhaust. What's going on?! =(

 

[mustang6]

Slipping balancer ring, that's about the only way your timing is changing without the distributor moving. Every adjustment you've made is now suspect. I would confirm it's slipped by locating TDC off a piston, and get a new balancer. I'll bet your timing is off by over 10 degrees but you can't tell.

 

[johnnyzoom]

Seems like that's starting to be a common problem with rebuilds done by outside mechanics...

 

[Mercury Mike]

Bust. The timing was jumping around back and forth about a half a centimeter while I was watching it with the light. BUUUUUST! I will try to locate a new balancer. BUST! Anyone got a spare one they can sell me? I'd appreciate it! =)