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-   -   Cold start a C2 (and probably others) (https://www.corvetteforum.com/forums/c1-and-c2-corvettes/4188729-cold-start-a-c2-and-probably-others.html)

mferreira2 09-16-2018 12:18 AM

Cold start a C2 (and probably others)
 
I have come out of my bunker in Austin because it finally stopped hitting 100F+ for the 50th day in a row. So, time to screw with the car more. This is my attempt to throw back some knowledge I have gained and maybe debunk some myths.

My car has been sitting on the lift for a while (weeks) because it was just too damn hot to work on or drive. Now that it cooled off, I figured time to blow out the cobwebs. I put her down and turned her over. It took three 10 second turns to get it to fire. So I thought to myself, self, WTF. I read all sorts of things about ethanol, evaporation, etc. I had convinced myself the bowls evaporated because I had just rebuilt the carb 3 months ago and it looked like someone put tar in the bowls from evaporation over a 10 year period. So I took the top off the carb, and low and behold, there was fuel. I revisited my thesis: Self, WTF.

Keep in mind I also have Marvell Mystery oil in the gas for multiple test reasons. So according to the fuel gods, it is not just ethanol BS. That rules that out. So I did some digging. Took the air cleaner off. Looked at it for about 6 beers worth...then realized...the choke isn't closing. I had heard the choke isn't supposed to close unless it was 50F and that if it was above that it should be open, at least a little. So naturally, I did what any sane person would do, and took it appart...again. What I found was the mechanism was sticking and lubed it up a bit. I reset it to two clicks clockwise and holy moly, the choke now closes at 90F...may sound stupid, but keep reading.

I did some research on cold starting. I know that sounds nutty also, but I did. EVERYONE on this forum says, pump the gas three times to get the accelerator pump to load the intake, wait, then turn over. My reaction was, that is stupid and gonna flood it. Well, I was wrong. I went from three 10 second cranks on a 24hour sit...to pump three times, wait for 10 seconds, and fire in maybe 1 second.

1. Make sure your choke closes
2. Pump the gas more than 1 time
3. ?????
4. Profit.

ChattanoogaJSB 09-16-2018 12:45 AM

My temps aren’t as high as yours but after weeks up on the lift mine fires off with no choke after a pump and a ten-count at most. It’s easily the most reliable starting old car I’ve ever had

mferreira2 09-16-2018 01:04 AM


Originally Posted by ChattanoogaJSB (Post 1597991690)
My temps aren’t as high as yours but after weeks up on the lift mine fires off with no choke after a pump and a ten-count at most. It’s easily the most reliable starting old car I’ve ever had

The real question is what do you do before 4. Profit?

ghostrider20 09-16-2018 02:43 AM

Did you check to see if your were getting a pump shot of fuel from the accelerator pump when you move the throttle?


Factoid 09-16-2018 05:46 AM

My ‘61 is also the most reliable starting old car I’ve ever had. One pump, turn the key and vroom vroom. I have an electric choke which means it will close anytime the element cools enough whether by the electric choke coil or ambient temperature. My bigger challenge is when the choke is on fast idle, shifting the 700R4 into gear is an adventure. However, the upside is the wife is almost too nervous to drive it!

Frankie the Fink 09-16-2018 06:09 AM

Cold starts after a period of sitting should be zero problem:


MikeM 09-16-2018 06:45 AM

If the fuel bowl in the carburetor is full, a couple of pumps on the gas pedal, a pause to let the fuel vaporize and the engine should start. Even in zero weather. No choke required to start but the choke action will help keep a cold engine running. Otherwise, if a cold engine tries to stall, a couple pats of the gas pedal will keep it running. Even in zero weather.

Some carburetors seem to be less prone to evaporation of the fuel than others. The WCFB that is on my '65 starts quickly after sitting idle for a few weeks. The AFB that was on my '63 would take about 10-12 seconds of cranking the engine to fill the carburetor bowls before it would start. Others report the same experience(s).

Dan Hampton 09-16-2018 06:57 AM

Stay away from oxygenated fuel.

MikeM 09-16-2018 07:28 AM


Originally Posted by mferreira2 (Post 1597991620)

It took three 10 second turns to get it to fire.

So I took the top off the carb, and low and behold, there was fuel.

I went from three 10 second cranks on a 24hour sit...to pump three times, wait for 10 seconds, and fire in maybe 1 second.

1. Make sure your choke closes
2. Pump the gas more than 1 time
3. ?????
4. Profit.

Did you write this before or after six beers?

Did you pull the top off the carburetor before or after the extended cranking?

Your "four points" are a mystery to me as to their meaning.

PS. Sounds like you might have a AFB?

Nowhere Man 09-16-2018 08:12 AM


Originally Posted by MikeM (Post 1597992060)
Did you write this before or after six beers?

Did you pull the top off the carburetor before or after the extended cranking?

Your "four points" are a mystery to me as to their meaning.

PS. Sounds like you might have a AFB?

his four points come from a old South Park episode. And I am laughing that I find a reference to that show on this board.

Also for cold starts read your owners manual

DansYellow66 09-16-2018 09:17 AM

There may have been fuel in the carb but it probably wasn't full which limits it's ability to charge the accelerator pump circuit until the pump picks up the load and fills the bowl. Also, sitting in the carb fuel bowl for weeks allows the volatiles to evaporate and when that stale fuel is shot into the carb throat/intake, it doesn't vaporize in the intake nearly as well as fresh fuel (mentioned by MikeM) which hinders firing. I still like self-priming my cars with a squirt bottle through the bowl vent after sitting for an immediate fire and start. But the practice of not touching the accelerator and turning it over for a couple 5-second spins - pump twice - wait a few seconds - spin the starter again, also seems to work well for many.

dplotkin 09-16-2018 09:48 AM


Originally Posted by MikeM (Post 1597992002)
If the fuel bowl in the carburetor is full, a couple of pumps on the gas pedal, a pause to let the fuel vaporize and the engine should start. Even in zero weather. No choke required to start but the choke action will help keep a cold engine running. Otherwise, if a cold engine tries to stall, a couple pats of the gas pedal will keep it running. Even in zero weather.

Some carburetors seem to be less prone to evaporation of the fuel than others. The WCFB that is on my '65 starts quickly after sitting idle for a few weeks. The AFB that was on my '63 would take about 10-12 seconds of cranking the engine to fill the carburetor bowls before it would start. Others report the same experience(s).

This has been my experience as well. 8 cars. The 2 WCFB's are cold blooded and need cranking to start. I discovered on my own that pumping & waiting for the vapors to linger and coalesce in the manifold is the trick for an expedited light off. The Edelbrock on my 440 New Yorker is no better even with its electric choke that I adjust seasonally. That car sits in a 100 degree tin can and the choke will not set.

The 2 Edelbrocks on the cross ram 440 need cranking but start easier than I would imagine...no choke on either carb and very long runners but when they have gas in them she fires once the bowls fill. The Holly on my 390 Ford once started better than it does now, I omitted Stable last season, that was a mistake. The 2 best starters? The WCFB in my 56 Caddy and the 4GC on my 327/250 Impala. The WCFB starts exactly as it likely did new. The Chevy is the odd one. No choke connected in the 18 years I've owned it. The car can sit for 3 months and will fire and idle out on the second crank. I didn't tune it for 10 years not wanting to wreck anything. Finally this season it began to stumble on left turns and I had it redone, was afraid its magic would be gone but no, starts the same way.

I think it a lot of factors, fuel, carb condition, ignition system and battery condition, temperature, humidity and even oil weight likely all weigh in to a greater or lesser degree. But I find the old 4GC & WCFB will start easier than the WCFB designs.

Dan

phil2302 09-16-2018 10:30 AM

One push on the gas about half way down on the Holley 3367 will sets the choke and a high idle (about 1500 rpm) regardless of air temp or how long its been sitting.
Fires right up every time. I let it idle high for a minute then hit the go pedal lightly and the idle comes down to 750. Yes there is ethanol in the gas. There is no alternative for me here unless I buy 5 gallon cans of racing gas and for my 327 300 I see no need.

MikeM 09-16-2018 10:39 AM


Originally Posted by dplotkin (Post 1597992540)

The 2 WCFB's are cold blooded and need cranking to start. The 2 best starters? The WCFB in my 56 Caddy and the 4GC on my 327/250 Impala. The WCFB starts exactly as it likely did new.

But I find the old 4GC & WCFB will start easier than the WCFB designs.

Dan

Are you confusing AFB and WCFB?

PS. I have a 3.0L Chevy engine in my pontoon boat. Not fuel injected. It can sit idle for two weeks, never touch the throttle to set the choke and/or give the engine a shot of gas and it will start right up and idle all day. Something is wrong with it. I don't know what but I'm not going looking for trouble.:D

dplotkin 09-16-2018 11:51 AM


Originally Posted by MikeM (Post 1597992771)
Are you confusing AFB and WCFB?

PS. I have a 3.0L Chevy engine in my pontoon boat. Not fuel injected. It can sit idle for two weeks, never touch the throttle to set the choke and/or give the engine a shot of gas and it will start right up and idle all day. Something is wrong with it. I don't know what but I'm not going looking for trouble.:D

No Mike, I have 2 OEM AFB and 3 Edelbrocks.

AZDoug 09-16-2018 12:18 PM

FWIW, Sta-Bil or similar fuel stabilizer is probably a better choice for long term fuel strorage than marvel mystery oil.
Doug

dplotkin 09-16-2018 12:41 PM


Originally Posted by MikeM (Post 1597992771)
Are you confusing AFB and WCFB?

So much for trying to type on a smartphone, yes Mike you are correct what I meant to say is that my afb's are a pain to start but the WCFb and for GCS start with the turn of the key.

Dan

Frankie the Fink 09-16-2018 01:54 PM

Whenever this old fuel bowl evaporation thing comes up I repeat my experience with dozens of carbs I've rebuilt....
I install them bone dry and the cars start within 5-7 seconds of cranking and pumping the gas....some might take a tad longer but very rarely...
That's AFBs, WCFBs and Q-jets...

toddalin 09-16-2018 05:19 PM

What's a choke?

https://cimg3.ibsrv.net/gimg/www.cor...43b12f79e1.jpg

Redbird 09-16-2018 06:37 PM


Originally Posted by Frankie the Fink (Post 1597991971)
Cold starts after a period of sitting should be zero problem:

https://www.youtube.com/watch?v=MkLM5jfMnYE

Frankie,

Video will not open!


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