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63riviera

cold weather starting problems in my '73 GS

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After doing a completely new ultra-high-energy ignition system, my '73 Boat ran soo much better--better throttle response,more Hp,torque,no bogs or hesitations and an increase in mpg (8.9>15.1)!!!

But because i have to park it outside in MN sub-zero weather (I have three other spots from other, better Buicks), I've encountered intermittent problems starting the car. Almost every time it has snowed here, the car will not start. The engine sounds like it's about to ignite and then doesn't.

Later when It warms up a bit, it may start, and then continue to run well, and start easily when cold. I've been through this three times

The choke mechanism appears to be working. But I noticed some gas accumulating by the carb. previously I had tightened down the 4 carb bolts.In the '73manual, it says on possibility might me a cracked or porous "Float Bowl". Could there be gaskets that need to be replaced. I read once that ethanol-rich gas attacks almost every rubber part in the fuel system.And in MN, we have ethanol-formulated gas. Also when it's cold, the volatility of gas changes. When running, the carb's performance is excellent--smooth idle, no stumble, good throttle response, etc.

This problem is bugging me!!!

Any ideas??? Please!

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It's running again very well. But this problem only happens after a snow storm (when the humidity is high).There's a procedure i found that works: Floor the accelerator to set the fast idle cam, crank the engine for 3 sec, pump the accelerator 3X, and then crank the starter and flip on the ignition w/o putting your foot on the throttle.

In my case, I find that i do Have to do the last step with the accelerator to the floor, so I think the carb must be flooded.

Anyway, this method works

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Steve,

One item that I would highly recommend for a 455 powered Buick that sits outside in Minnesota is a block heater. It will make that BBB start like it's a sunny June day outside! It warms the coolant in the block and can even warm the oil up somewhat to help cold flowability. The oiling system on these engines leave a lot to be desired with an external oil pump and and exceptionally long oil pick up system. Extended cranking with a 455 may be a God-send because it allows the oil pressure to come up somewhat before the engine fires and runs at high idle speed when the engine is cold.

Generally speaking, humidity is more of an influence on ignition systems than it is on carburetion. Just make sure that the choke is closed fully when it is cold, there should even be some tension on the choke plate to keep it closed. Most 73 Buick Quadrajets just use one choke pull off, and it must be operating properly or the engine will "load up" or smoke out the tail pipe and run rough until the choke spring is heated enough to open the choke.

HTH,

Tim McCluskey

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On the carb issues, the cold weather should not be allowing the fuel in the float bowl to evaporate (as might happen on a hot day in Arizona after shutting off the engine after an extended freeway run with the a/c), so the fact you have to pump the accel pedal three times makes it sound like the fuel is not as volatile as it should be, BUT the fact that your procedure has the "starter for three seconds" might further indicate that the float bowl is pretty empty.

I know it's cold during these starting procedures, but have you checked how much accelerator pump "shot" is actually coming out in those three pumps? That might be further indicative of how much fuel's in the bottom of the float bowl. The other comment about "seems like it's flooded" tends to confirm a carb situation.

On Rochester QuadraJets, there are two plugs that are soldered into the bottom of the float bowl when that casting of the carburetor is assembled--secondary well seals. With age or whatever, they can start leaking and result in a "hard start" situation as it allows the float bowl to drain into the intake manifold. This is especially noticed on the first cold start of the day. The "seep" is not really a "leak", but it still allows the float bowl's contents to disappear over an extended period of time. As you might know, the float bowl capacity of Rochester QJets is not that great anyway (compared to some other carburetors).

This is a known situation for QuadraJets and there are many methods to fix it, but they all require disassembly of the carb (might as well "kit" it too, as everything will be apart). This situation was around back when gas had lead in it, so I doubt the ethanol content has anything to do with it. I suspect the only parts of the carb which might be affected by the ethanol-laced fuel would be elastomeric-type seals and other parts rather than paper-type gaskets.

One thing I found deep in the carb parts listings in mid-1980s GM parts books is a special accelerator pump listed for "export" and "high aromatic fuels". I later found out that "high aromatic fuels" would be ethanol as used in Brazil, as "Brazil" was noted somewhere with that different fuels notation. I never did see one of those accelerator pump plungers, but that's the only real issue that might relate to your ethanol content fuels up there (which I believe is a higher content than in other parts of the country?). Since the mid-1980s, I believe that factory fuel systems have been E15 tolerant?

So, to me it sounds like you have the normal secondary well seals issue on your QJet. There are several fixes, one is to spread some two-part epoxy sealer on the seams (solder joints) and another is a foam pad that fits under them when you assemble the carb. Check with your local mechanics and see what they prefer.

If it still acts like it's loading up during warm-up, you might adjust the choke thermostat coil a notch or two "leaner" as the choke thermostatic coils can gain strength with age so you would need to back off of the factory spec adjustment to compensate for that. Make sure that the vacuum break is working and strong enough to pull the choke valve open (when the engine starts) against the choke spring's force). Sometimes, you have to tweak and finesses these adjustments on an older vehicle to get things to work correctly in more modern times and different fuel compositions.

Just some thoughts,

NTX5467

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When I have run into starting issues after rain, snow, or very humid cold days in my Buick's, turns out I had either a hairline crack in my distributor cap (could not be seen until I applied pressure inside the cap outward) or I had faulty spark plug wires.

Simple easy fixes to try first.

David

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