Carb Issues

BillCNC

BillCNC

Well-known member
Hello All,

I just picked up another air balanced, flow tested rebuilt carburetor the other day and I put it on my car to see how well it runs.

To run it it needs 1-1/2 to 2 turns on the GAV, Obviously runs rich. When I try to turn the GAV in, it starts running ruff and if I turn it all the way in, it dies.

Anything come to mind?

Regards
Bill
 
Synchro909 said:
How does it run at driving speeds with the GAV screwed almost in?
Click to expand...

Thanks Synchro,

At 35 it bog's down pretty bad like it's starving for fuel so I open it up and the car runs fine. At slow speed it smells like gas is pouring out the carb, ... but it's not. I'm afraid I might be running to rich resulting in washing the cylinder walls of it's oil.

Regards
Bill
 
I would go back to where you "just picked up" the carb and get some satisfaction from the rebuilder. This is not right, the car should run with the gav at a 1/4 turn or so. Jack
 
Taking the carb back is not an issue as he's my brother in-law. He rebuild's carb's as a side business and has started working on "A" Zenith carbs. He's rebuilt 3 prior to this one for me and they all work great except this one. He's about 60 miles from me and I was just wondering if someone had a clue as we're both kinda stumped. I was hoping it was something simple like the GAV is defective, wrong jet sizing or something like that. Maybe I'll take the carb apart tonight and have a look.

Regards
Bill
 
Pull a plug, look at condition. Like Katy indicates, new carb, and with new jets - adjustment is necessary.


Not sure where you got the replacement jets, preferably you bought them from somewhere that flow tests them. Replacements frequently/occassionaly do not to flow correctly.


Renner's Corner flow tests their replacements before shipping. In my A they made a big difference in motor running smoothly, more acceleration, more torque especially going up hills, and plugs are now a nice tan . Before they were not sooty, but were a little on the black side on the center insulator. More expensive but worth if.
 
30 Closed Cab PU said:
Pull a plug, look at condition. Like Katy indicates, new carb, and with new jets - adjustment is necessary.


Not sure where you got the replacement jets, preferably you bought them from somewhere that flow tests them. Replacements frequently/occassionaly do not to flow correctly.


Renner's Corner flow tests their replacements before shipping. In my A they made a big difference in motor running smoothly, more acceleration, more torque especially going up hills, and plugs are now a nice tan . Before they were not sooty, but were a little on the black side on the center insulator. More expensive but worth if.
Click to expand...

Hi 30,

ALL my parts for all 4 of my carbs came from Renner's Corner, so they are the real deal. The carb bottoms were sent there also and they did the air balance passage machining which is why we're stumped.

Regards
Bill
 
If you have another carb, or a spare GAV needle, swap it in. When you do, inspect the needle and teh seat. Maybe one or both are damaged.


If you do have another carb, swap the bottom of the carb, at least would narrow things down slightly. Easy to do, do not even half to remove the carb from the A. I had to do this recently on a spares carb I was having problems with.


Are you sure you do not have a leak at the Carb/Intake manifold, or at the intake manifold letting air into the air/fuel mixture?


One of the things I had to do was to put a little sealant on the jet threads being careful not to allow teh sealant to get into the carb. Some will say do not do this. I used a Permatex product, is white and soft. Did not use Teflon tape, thought a piece might get into the carb and block things. It helped me cure an issue.


Just s few suggestions, I found out on my carb, carbs can be exasperating to fix.
 
Hi BillCNC
In the last week I purchased a NEW " Air Balanced Carburetor" from Synders, just so I could install a air filter on the carburetor' and I have nothing nothing but problems with the new carburetor.
The first one Synders sent me leaked gas through the casting ( I think it was a pin hole in the casting) Called Synders they sent me out a replacement for the defective one.
The second new carburetor from Synders didn't leak gas, but it wouldn't let the car run over 30 mi. per. hr. also it wouldn't run or idle down unless the GAV was open 1 to 1 1/4. I removed the air filter and that didn't help so I gave up and put the old stock ZENITH back on w/ no filter the motor ran ok. (if its not broke don't fix until it is broke)

I returned both carburetors to Synders and canceled my order. Snyders quality has been very good, I think they just got a bad batch from there supplier.

Regards farmerjohn
 
Hi Farmerjohn,

Well this one needed to be rebuilt, ... it started as empty set of castings needing to be populated with every part.

Odd thing is, I can get it to idle perfectly ALMOST 80% of the time. The other 20%, it's a handful when coming to a stop. It runs very nice at 50-55 mph. Recently while doing a search of my problem I saw an old post of Bill Williams that said to dial in the GAV at 20-25 mph in second gear. Once set, I think it was 1.5 turns it ran fine until I came to a stop sign, ... the car died. Starting it again requires the GAV to be turned out to 2 turns or so.

Iv'e been reading a couple of books by Steve Pargeter today.

1) Zenith Model "A" Carburetor Restoration Guidelines
2) Model "A" Ignition Primer & Restoration Guidelines

The Ignition book's cover say's "90% of all carburetor problems are electrical" so I guess that is also something to consider. But for the GAV?

Perhaps, taking the carb apart and cleaning it, checking that nothing is stuck in an orifice or the passageway's and checking my float level might do it. Or perhaps checking the electrical might be in order. I not completely sure if electrical could be the problem if I'm only having issues with the GAV settings. But then again, ... this is still new to me, ... almost 2 years in the hobby.

Heck, I'm still trying to figure out how the average person took care of these Swiss Watches of a car compared to a modern car, only to be armed with minimal tools and knowledge at best.

Regards
Bill
 
30,

I'probably could start swapping part's from my other's, but I think that's going to be plan "B". I'd hate to start playing around with perfectly functioning carburetors only to end up with another one acting a little squirrelly.

Regards
Bill
 
BillCNC said:
30,

I'probably could start swapping part's from my other's, but I think that's going to be plan "B". I'd hate to start playing around with perfectly functioning carburetors only to end up with another one acting a little squirrelly.

Regards
Bill
Click to expand...



I understand, this was a last resort, also had fears of messing up my good carb. But ran out of ideas so tried this.
 
farmerjohn39 said:
Hi BillCNC
In the last week I purchased a NEW " Air Balanced Carburetor" from Synders, just so I could install a air filter on the carburetor' and I have nothing nothing but problems with the new carburetor.
The first one Synders sent me leaked gas through the casting ( I think it was a pin hole in the casting) Called Synders they sent me out a replacement for the defective one.
The second new carburetor from Synders didn't leak gas, but it wouldn't let the car run over 30 mi. per. hr. also it wouldn't run or idle down unless the GAV was open 1 to 1 1/4. I removed the air filter and that didn't help so I gave up and put the old stock ZENITH back on w/ no filter the motor ran ok. (if its not broke don't fix until it is broke)

I returned both carburetors to Synders and canceled my order. Snyders quality has been very good, I think they just got a bad batch from there supplier.

Regards farmerjohn
Click to expand...

From what I have heard, most of the new carburetor parts from vendors have issues (especially leaks). And the new carbs are the worst for quality. Have to be made overseas. When it comes down to it, most OEM parts are better and longer lasting than the junk that is being sold today.
 
chrs1961815 said:
From what I have heard, most of the new carburetor parts from vendors have issues (especially leaks). And the new carbs are the worst for quality. Have to be made overseas. When it comes down to it, most OEM parts are better and longer lasting than the junk that is being sold today.
Click to expand...
Which is the most disturbing part.

All these parts are being made on CNC machines, with accuracy that Henry could never have possibly imagined even in his wildest dream's. These parts should be 10x better made, period. They should have higher quality of accuracy with higher quality metals than the originals.

The REAL problem is Human's. A CNC WILL make a part EXACTLY as programmed 100% of the time. It must be checked periodically for tool wear and the tool offset's programming adjusted, or the tools need to be replaced to keep tolerances. Adjusting the offset's is the norm.

If a part made is wrong:

The programming is wrong = Human error
Tool Wear = Programming = Human error
Part moved in vise = Human error
Tool Breakage = Human error
Part setup wrong = Human error
Machining known defective part's = Greedy Human error

Vendors buying know incorrect part's = Greedy Human error

Regards
Bill
 
jm29henry said:
Does your brother in-law test his carburetor before sending them out?
Click to expand...
Mine are his first model "A's".

I'm not sure how he deals with the rest of the brand's. I know he does mail order and has a few LA/orange county car dealership, parts houses as clients.

Regards
Bill
 
I used Renner's Corner tool #RC-9599-Z, Zenith Carburetor Fuel Level Setting Gauge to check the bowl level setting and it come to .0625" (5/8's) from the seam. I started the car a couple of times with the tool installed so it would refill it for another measurement. It's .625", every time. So it's time to remove the carb for disassembly.

Regards
Bill
 
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