vaccume guage questions

[johnblaid]

Vacuum guages questions...needles jump wildly

I bought a good carb sync kit off amazon...about a hundred dollars. have seen pix of this kit on these forums and people say they work.

saw a YouTube vid of a guy syncing his carbs.

the gauges were holding steady at about 15 or 20 in the vid. needles were steady.

my gauges jump back and fourth from about 10 to 30 very very fast after getting them as close to equal as I can.

I don't think this is normal. is there a vacuum leak somewhere or what?

 

[texmax]

Don't know what brand sync tool you have. You could be missing the restrictors in the tubes, that tends to make the guage jump around a bit. I'm in Aubrey with a Morgan Carbtune if you want to use it and see if you get a different reading.

 

[leroycp]

As above, make sure you have installed the restrictors. Place restricted end closest to carb port.

 

[Miles Long]

You have to put restrictors in the rubber tubes. In my case, using 5/16" windshield washer tubing, #10 x40tpi brass machine screws, 2" long, worked great. Just cut off the heads and put in the vacuum port end of the tubes.
The air is forced to follow the threads of the screws. My gauges stay rock steady.
Cheers!

 

[06VMAXIMUS]

I think some one here on the forum mentioned using the inner plastic shielding from cable TV wire as a restrictor....

 

[johnblaid]

This is it and no, I did not put any restrictors in it. DUH...


After reading, I thought I had weak valve springs. It IS an 86 but only has about 18000 miles on it.


The screw trick sounds good.

 

[1st Shirt Maxer]

I have the exact setup as you, there are no restricters with this setup. What you do is turn the knurled bottom portion of the gage where the hoses are attachéd to the gage to calm the needles down. This gage setup has internal restrictions to help reading the Gage's when in use. Just be careful because you can close the vacuum completely and the needle will no longer move with the vacuum.

 

[johnblaid]

and I'll just bet that if it had come with any instructions, that would have been mentioned.

thanks.

 

[1st Shirt Maxer]

I hear you. I was lucky that I had someone very knowledgeable to call when I was trying to learn how to sync the carbs. Good luck

 

[johnblaid]

yea I only see three screws, two on the right and one on the left.

I'm gonna look into that.