bench sync procedure

[indyjoel]

Hi need some help to save my sanity

I am have tried to bench sync twice and stuffed it twice

Once I synced them too tight (not starting) and then I must have synced them to large (revving to 4K)

Am I doing this right?

1. Set air screws 1 1/2 or 2 1/2 turns from bottom [from lightly seated].
2. Put a small paper clip under the butterfly of the master carb The one the throttle cable connect to.
3. Adjust the main idle screw until the butterfly just touches the paper clip.
4. Adjust the sync carb #2, then carb #1m then carb #4 screws until all of the butterflys have the same gap with the paper clip.
5. Check the master carb again to see it is just touching the paper clip
6. Reset the idle screw back out all the way to close the throttles back down, then back in about a turn or two.

However what does this mean
Ms. SqDancerLynn1: The only thing I would add is to make sure the #3 throttle blade is completely closed with the idle screw backed out. You never know what was done in the past.
Does this mean when I reset the idle screw the #3 butterfly is completed closed?

Mr. Steve (again): Ms. Lynn makes a good point. What I tend to do when finished is to back off the idle screw until there is a gap in the adjuster, then shine a light through all the carb throats to verify that they all are closed. Then do a visual sync as I turn the idle adjuster until it touches, then about one turn more.
Do I need a small gap in the #3 butterfly valve or no gap?

[Nessism]

A small gap is fine, the engine needs air to run.

Honestly now, sounds like you are putting more work into the bench sync than necessary. They just have to be close enough to run so a proper vacuum sync can be performed. I just eyeball the carbs and fire it up.

[Steve]

Yep, just eyeball the carbs. I don't even worry about the paper clip any more, I just look for the sliver of light.



You probably had the bench sync part reasonably close, you just didn't have the master idle speed adjusted correctly.
That is somewhat normal. I don't think any of us gets it right the first time.

.

[indyjoel]

Yep, just eyeball the carbs. I don't even worry about the paper clip any more, I just look for the sliver of light.



You probably had the bench sync part reasonably close, you just didn't have the master idle speed adjusted correctly.
That is somewhat normal. I don't think any of us gets it right the first time.

.

You are all right.I am overthing the bench sync.

What worries me is that I fully backed out the master idle speed adjuster and it was still revving to 4K until I undid the butterfly valve screws only to check my sanity.

[SqDancerLynn1]

depends on weather you have VM or CV carbs. principals are the same.
I start with the #3 carb closed to get a baseline. Just in case someone has got it way out of adjustment every thing hinges on #3 being correct
If the idle screw is backed out the throttle slide should be closed If not it needs to be adjusted first.

[indyjoel]

i know i am jinxing myself by posting but...

re bench synced, put the carbs on, would not kick.

adjusted the idle screw couple of times and...

SHE STARTED and idles at about 11-1200.

I throttle on and she pulls clean and returns to same idle.

Let her sit for a couple of hours and restarted same thing
another couple of hours and still good.

Let's see how it goes over night sitting and trying to start

thats the big test.