carb question 72 vega 2bbl

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carb question 72 vega 2bbl

Postby gotmud7 » Thu Mar 18, 2010 7:57 pm

I'm trying to get the Vega running after sitting all winter. It didn't run well all last year. With the hood up, no air cleaner on, idleing. There was gasoline spurting out of what I beleive is a vent tube. Could this be from the float being set too high? I "rebuilt" the carb last year. Never ran right since. Any ideas? Oh yeah. Stock 140 with Rochester 2bbl. Thanks Mark
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The only Vega's that only had a little rust were the ones still on the assembly line.
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Re: carb question 72 vega 2bbl

Postby cosvega76 » Fri Mar 19, 2010 1:38 pm

Mark,

If you have fuel spilling out of that tube by the "T" of Tube in your label, you have a needle and seat that isn't sealing. Try pinching off a fuel hose at some point before the carb - or remove the fuse for the fuel pump (or oil sender switch plug) if you're still using the electric fuel pump - and let the car run until it runs out of fuel in the carb and dies. Then remove the pinching device, or replace the fuse or plug, and start it up again. Sometimes a bit of debris gets caught in the needle and seat, and this may help dislodge it.

If that doesn't fix it, you will have to take the top off the carb and check the float and needle and seat for proper installation and free movement.

Chuck
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Re: carb question 72 vega 2bbl

Postby gotmud7 » Fri Mar 26, 2010 5:30 pm

Thanks Chuck. I ended up taking the top of the carb off and readjusting the float. Next I set the timing. 8 degrees BFTDC as best I could eyeball it in the sun. It idles much better now.
Update: I drove the vega slowly around the block. Runs good for a 4 cyl Vega. When I tried to get out on the main roads it just died when I tried to take off. It made a couple of popping noises like it wasn't getting fuel and died. It started up after some cranking and I limped back home. Again drove ok slowly.
Today I took apart the carb again, actually measured the float when setting it. 19/32 upside down to the seam in the brass float. and 1 and 7/8 it said for float drop. I did it slighlty less than that because the needle valve seemed to come out too far and get hung up. Engine fired right up, idled fine. I could even hold it a 2500 RPM for about 30 seconds without any problems. Backed onto the street, and it popped and hesitated when I tried to drive it. WTF?
Any ideas? The glass fuel filter right before the carb always looks full. I know I put the brass fuel filter into the carb correctly with the spring. I checked all the sparkplug wires to see if they were loose. I have a Pertronix ignition (no points) and coil. Edelbrock aluminum intake, headman full length headers. Running a very small round airfilter so I can adjust the carb with the airfilter on it.
I also replaced the TH350 "modulator" last year. Didn't really drive it since either. I have had the Vega 3 years now and only drove it about 150 miles. It just sits in the garage.
Mark, I need a V8.
The only Vega's that only had a little rust were the ones still on the assembly line.
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Re: carb question 72 vega 2bbl

Postby cosvega76 » Sat Mar 27, 2010 7:08 am

Mark

"Popping noises" makes me wonder if it's an ignition problem now. I'm not familiar with the Pertronix (although I want to put one on the wife's '67 Mustang), but try disconnecting the vacuum advance for a try. There's a possibility that with the breaker plate moving with the advance that the Pertronix unit may either be moving too far away from the distributor cam for an accurate trigger, or maybe the wires may be getting pinched or have a break that is opening the circuit. Try gently tugging on the wires to see if they are "elastic" - the conductor is separated but the insulation is intact.

Or...we need to get together for a Tech Day.

I can understand your frustration of having the car running and not being able to drive it.

Chuck
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Re: carb question 72 vega 2bbl

Postby 73astregt » Sun Mar 28, 2010 9:53 am

im probably way off here but accelerator pump no good maybe? have you checked compression? a friend of mine had problems with a 302 ford that would pop back thru the carb above 3000 rpm,ran fine at idle and low speed ended up being a cylinder with a groove worn in the side didnt find the problem till he removed the heads. hope im wrong here . i know you said it didnt run good after you rebuilt the carb last year but you never know...
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Re: carb question 72 vega 2bbl

Postby gotmud7 » Sun Mar 28, 2010 6:35 pm

Today I pulled the top of the distributor off. How much rust is acceptable? I cleaned up the weights and springs and made sure everything moved. I also made sure the vacuum advance was working. Then I adjusted the timing again, no vacuum. I was about 20 degrees too far advanced. I don't get it, I just adjusted it last week. It idled kind of crappy, but I talked my 8 year old son into going for a ride. We went about 10 feet and it started popping again - then the brakes went completely out.

I made my son walk home, I coasted the vega down the block into the driveway. Made my son push it into the garage while I steared. He didn't like that. Turns out my front drivers side hose has a holein it from rubbing the a-arms.

Doesn't go, doesn't stop. Mark
The only Vega's that only had a little rust were the ones still on the assembly line.
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Re: carb question 72 vega 2bbl

Postby cosvega76 » Mon Mar 29, 2010 9:44 am

Uh-oh...the timing changed 20 degrees?

Better look at the timing belt and see if it's in time. Sounds like it slipped.

Chuck
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Re: carb question 72 vega 2bbl

Postby gotmud7 » Mon Mar 29, 2010 10:50 am

Timing belt? I guess I never thought about a timing belt. I'm not used to inline 4 cyl stuff, especially overhead cam. I was thinking the distributor might be worn. It's got a few degrees of wiggle to it when I had the top off. Meaning I could grab the shaft at the top and it would rotate either way just slightly.

I'll have to pull the front cover off the timing belt. I am assuming that there should be 2 marks that line up. One on top sprocket, and one on the bottom? Or am I thinking about the cam timing? Dang 4 cyl!

Mark
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Re: carb question 72 vega 2bbl

Postby cosvega76 » Mon Mar 29, 2010 4:08 pm

Boy, let me get out the Wayback Machine, Sherman! (reference to an old cartoon)

If my memory serves me correctly, you should be able to set the crank at TDC, and there should be a hole on the back side of the cam sprocket shroud to peep in and see either a hole in the cam sprocket, or a raised notch, or something, if it's in time.

It's been a loooooong time since I worked on a standard Vega 140.

Chuck
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Re: carb question 72 vega 2bbl

Postby gotmud7 » Mon Mar 29, 2010 4:40 pm

Was it Mr. Peabody, or Prof. Peabody? I ordered a new belt from Rock auto today. $7. Along with new brakelines. I'll have to get out the manuals and do some reading. Thanks Chuck
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Re: carb question 72 vega 2bbl

Postby cosvega76 » Tue Mar 30, 2010 8:54 am

Mr. Peabody it was!

I hope you ordered a water pump gasket, as well. The water pump is used to tension the belt. I have the tool to use with a torque wrench to tension the belt that I can lend you, if you need it.

Chuck
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Re: carb question 72 vega 2bbl

Postby bugdewde » Wed Mar 31, 2010 8:11 pm

gotmud7 wrote: I am assuming that there should be 2 marks that line up. One on top sprocket, and one on the bottom? Or am I thinking about the cam timing? Dang 4 cyl!

Mark



The cam sprocket will have a hole/indention on it that will line up with a tab on the head.
The crank will have a hole in it that will line up with a notch cast into the cover.

See the second page of this thread..... about 11 posts down to see the pics of my timing marks on the 140.
viewtopic.php?f=2&t=24291&start=15
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Re: carb question 72 vega 2bbl

Postby gotmud7 » Wed Mar 31, 2010 10:45 pm

Hey thanks for the link to that thread. It totally sounds like what is happening to my car. I'll check the timing, then reread the carb tuning again for like the 30th time. Mark
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Re: carb question 72 vega 2bbl

Postby gotmud7 » Wed Apr 21, 2010 4:09 pm

I finally got to work on the Vega today. I checked the timing (6 degrees, but should be 8), then I adjusted the carb the best I could. Then went back and set the timing. No vacuum, in neutral, idleing. When I revved it up, the timming did not change with the timing light. It stayed at 8 degrees. Um, isn't the timing supposed to increase as the rpm's increase because of centrifcal force? If you lok at one of my past posts in this thread, I stated that I took apart the top of the distributor while still in the car and cleaned the weights off. When it went back together, I see the timing was off by 20 degrees. Sounds like the ditributor is not advancing which is causing the dying out under load. Driving around the block probably just used enough rpm and load where the vacuum advance was making up for no mechanical advance.

What's the solution? New rebuilt distributor from ebay ($27), or take out and really clean the one I have? Mark
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Re: carb question 72 vega 2bbl

Postby 73Vegaguy » Wed Apr 21, 2010 9:49 pm

With the vacuum advance disconnected you should be able to see the timing advance when the engine is revved. If it doesn't then the weights are sticking. I'd clean and lube everything well and recheck. Most Vegas can benefit from a faster advance rate, so heavier weights and/or weaker springs can help too.
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