'74 GT380 carb reassembly question

[jbswear]

I finally decided to try and remedy the GT that I've had, non-running, for nearly three years. Again. Some of you may remember my most recent troubles: Running on one cylinder. If I sprayed brake cleaner into the other two carb throats, they would fire.

So I took them all apart and put them in a sonic cleaner with Simple Green for a few hours, then blew out the passages with an air compressor. Noticed a lot of junk in there; hopefully this will fix it.

While I was in there, I raised the needle jet's clip on each carb to the third slot, as I'm running pod filters and would rather have a bit too rich over too lean. Still running stock jets for now. If this gets it running, I'll read the plugs and change the main jets if needed.

Anyway, I'm putting them all back together now. I forget what the parts are called, so bear with me...

On the yoke that holds the three carbs together...The threaded rod that runs from the slide up through the yoke...that 14mm hex part that the accordion boot attaches to---how far do I thread the rod through it? Until it bottoms out? A certain other length?

I know the top 10mm piece is used in conjunction with the threaded rod to bench synchronize the carbs, so I'll do that after I get it all back together.

Thanks!

[jbswear]

Also...

I'm missing two springs--on for the idle adjustment knob and one of my air screws is missing a spring.

Where should I look to replace these?

[jbswear]

I think I figured out my answer...After setting the height with the 10mm and the threaded rod, you then tighten the 14mm against the bottom of the cross member?

Is that so?

Still wondering about the springs, though...

[Buffalo-guy]

The adjuster rods should be set to allow the slides to close completely, with a little to spare. Balancing them should take care of the rest. As for springs, I got lots. How far away are you, and how long can you wait for them to arrive? I'm in Calgary Alberta, so they could take a few days to get there. Let me know. Cheers.
Fred

[Coyote]

Jason, I have the needed springs as well.

Spin on the lower (boot holder nut) first. All the way down is OK for now but not tight. Insert the slide rod through the pivot an then the top nut as shown.
To bench sync the carbs after assembly, run the throttle stop all the way down and back it out 1 1/2 to 2 turns. Get a small paper clip and straighten it out. Raise the slide on any carb and lower it on the paper clip. Hold the top nut with a wrench. Usig a screwdriver, turn the throttle rod untill the paper clip is a slip fit under the slide. Continue to hold the screw and raise the lower nut up to the pivot. The upper and lower nuts jam together to hold the slide in position. I may take a few trys to get the paper clip to be a nice slip fit under the slide. Repeat this procedure with the other two carbs. This is all done on the breather side ie. you'll be putting the paper clip wire under the slide cut away.
This is all explained in the CD I sent you. I did send you one didn't I?

[jbswear]

Coyote--

Yeah, it's there. I understand the syncing process; I just had a brain fart while putting the carbs back together (of course I didn't have the manual with me at the time). I'm not looking at the CD right now, but I believe that measurement (paperclip) is 1mm or so, right?

Whichever of you wants to send me the springs, let me know how much you want for them plus shipping to 20716. Fred--seems you're the man for carbs; you sent me a carb body some months ago to help me out!

[Buffalo-guy]

Seems to me I had a brain fart once. Dam near blew my head off. PM has been sent. Cheers.
Fred

[Coyote]

Actual spec is 0.8 - 1.0mm or .031 - .039 . Paper clip is about .033. I guess I slept since then. That setting is made on the engine side. DUH!

[jbswear]

Another couple of questions...

First, for the enricher/choke level--the check ball and spring are inside, but it won't lock into "choke". I have to hold it in place to choke the engine. The plastic washer and the lock washer are on the screw that holds it in place.

Should I try using a longer spring?


Then...in syncing the carbs...I can get the left and right carbs perfectly set, but not the middle. For the life of me, I can't get the middle slide to raise with the other two. I mean, it rises, but there's "slack" in the travel. The other two slide lift as soon as I rotate the bar, but the middle sits until the other two have risen about a millimeter. The only way to remove all the slack is to raise the lower 14mm adjuster nut so high that I then can't adjust the slide any higher.

Any hints?

[Coyote]

Are you sure the check ball didn't fall out? The spring can be stretched a little, then use a dab of grease to stick the ball on the spring while assembling the choke rod. The lever should 'snap' firmly in both positions. Is the guide plate that centers the throttle shaft in place? If not, everything can shift and you would lose the tension. I might have a spare spring if yours has fatigued.

As for the carbs, try slackening everything off and setting the center slide first. Then adjust the outer 2. There's a happy median in there somewhere.

[jbswear]

Are you sure the check ball didn't fall out? The spring can be stretched a little, then use a dab of grease to stick the ball on the spring while assembling the choke rod. The lever should 'snap' firmly in both positions. Is the guide plate that centers the throttle shaft in place? If not, everything can shift and you would lose the tension. I might have a spare spring if yours has fatigued.

As for the carbs, try slackening everything off and setting the center slide first. Then adjust the outer 2. There's a happy median in there somewhere.

Yes, the check ball is in there. I pulled it apart to test it. I'll try stretching the spring. I'm not sure which part of the assembly is the guide plate.

Last night, while lying in bed, I think I came up with a fix for the center slide. The little bracket that the rod goes through and is screwed into the slide--bend that tab down just a bit so that the rod doesn't move up before pulling the slide up with it. I'll let you know if it works!

[jbswear]

Success!

I stretched the check valve's spring a slight bit--it's surprisingly stiff and tensile.

I also bent the threaded rod's bracket down about a millimeter which removed the slack. Now all three are synched as close to each other as I can get it.

Now then...mount these bad boys up and see if it'll start!

Thanks!

Oh, and thanks to Fred for (again) coming to my rescue with parts!

[jbswear]

It runs!

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