my1st7

I FINALLY found a vac leak on my 82 fb. Car would not idle for 5 months, but i could drive it. Spraying start fluid right near phenolic spacer on driver side. Just above the tubes that rats nest connnect to carb. Mostly right where shutter valve pin from carb comes out to connet to shutter valve. Do you need a pick ?? When spraying that area it idled perfectly, just like the good old days. I had just about given up. Where should I start from here ? Please help.

twinkletoes

iTrader: (17)

If its the shutter valve you can just put plug it and it will be fine. Won't hurt anything.

my1st7

When idle problem began, Shutter valve was howling. I replaced the shutter valve with a brand new one. The howling stopped but would still not idle. If i pull it and block it. How do you pull that peg that comes out of the carb? Is this a common place for a leak? The leak is not back behind where shutter valve connects to carb with gasket and bolts.

blackdeath647

iTrader: (2)

i have a bit of trouble following your last post, if you have pics, that will help a lot

Jeezus

iTrader: (4)

Your spacer is leaking? I am confused.

EDIT: I got one here if you need it. Pay for shipping and its yours.

74RX4

iTrader: (10)

There are 6 vacuum lines and 2 gaskets in that area. I've seen cracked spacers leak air also. I think it is way more likely that one of these parts are leaking. Did you replace the gaskets when changing the shutter valve? I think the shutter valve shaft in the manifold is sealed with a brass bushing, not any type of soft seal or gasket.

my1st7

Did it again. Most of my success came directly at the mixture screw. Mine still has the metal cap over it. I think I would like to start there. Yes, I did replace the gasket at the shutter valve. When I spray there I dont get any surge. What should I do about the mixture screw?

74RX4

iTrader: (10)

While it is possible, I doubt the mixture screw is leaking. I'd make sure none of the vacuum lines in that area are cracked. Remove them one at a time and blow into one end while holding your finger over the other end.

mazdaverx713b

iTrader: (91)

^^bingo. that would be the first step. when in doubt replace each line as you have it off. preventative maitenance you know.. at any rate if that yeilds less than favorable results check the carb spacer for cracks or ripped gasket. i've had tons of carbs off over the years and have never had to replace that gasket so the chances of yours being bad is unlikely..unless someone was monkeying with it or had gouged the mating surfaces.

my1st7

I checked vac lines. Then replaced each line.
couldn't find any cracks and new lines didn't change my situation, but they look better. I remember before this started trying to get that cap off the idle mix screw.
I used channel locks and used alot of force to unscrew and pull it.
this was before I read you cut it off.
but, could I have damaged something the cap connects to ? Or should I pull the horn and check the spacer? I hate to give up after so long and after I finally found the leak. I do appreciate all your help.

blackdeath647

iTrader: (2)

doesn't the rebuild kit come with one? i think mine did, but can't remember

my1st7

I removed spacer to check it. Here are the pics of it. Right where I thought the leak was is signs of fluid I sprayed to find leak. The fluid goes all the way to carb throat. I had it bolted down as tight as I could. Do you think I just didn't have it down tight enough or is there somehting wrong with the spacer and be replaced. Also, Should i go ahead and cut off the mixture screw cap while I have access to it? Or is it better to leave it on?

my1st7

Is there supposed to be a gasket on either side? I read the thread on Phenolic spacer and someone trying to scrape off gasket. I don't see one.

74RX4

iTrader: (10)

What did the gaskets look like? I doubt tightening it down more will fix it. Everywhere else looks like it was sealing. My guess would be either the gasket or the spacer is damaged or maybe some debris was trapped between the gasket and body. You might check the spacer and carb body with a straight edge.

74RX4

iTrader: (10)

Yes. There should be gaskets on both sides.

my1st7

straight edge shows that it is flat. After cleaning and closer reveiw, there are is a gasket on each side. They super thin but in good shape. I think maybe some debree may have been in there. Is it worth my time to try this one again or just get a new one??

74RX4

iTrader: (10)

They are very thin gaskets. If it were me I would make sure it is very clean and try it again. You don't seem to have any problem removing and installing the carb. For many people that is a fairly challenging task.

my1st7

I cut off the mixture screw cap. I replaced the spacer. Did not idle. I adjusted the mixture screw and now it idles right at 800. A very slight hesitation when hit gas.
Am I just masking another problem doing this? How could that mixture screw have gotten out of wack with that cap over it ? Never even attempted the idle screw because it wouldn't idle below 1500.

blackdeath647

iTrader: (2)

i would guess it's TOO lean, or the revs are too low, might still have a very small vacuum leak.

74RX4

iTrader: (10)

I would try adjusting it in 1/8-1/4 turn at a time and road test to see if that hesitation goes away. If that doesn't work try turning it out the same way.

You might have stirred up some junk in the bottom of the float bowls and some of the jets or passages are slightly blocked. That could cause the mixture screw to need adjustment. How far did you have to turn it? 3 turns out is the initial factory setting after rebuild. Should end up between 2.5-3.5 turns out after final adjustment. Maybe a can of Sea Foam in a 1/2 tank of gas to try to clean it out?