C2 - 63 WCFB

[Harry Sadlock]

I am amazed at what happens over the winter when the car sits in the cold. Anyway, two questions on my WCFB on a 250 hp 63.

1) I'm adjusting the choke, what should the rpm's be when the choke engages on a cold engine? I've checked all of my doc. and it's not there, is it in the PV doc.?

2) Also, if the car sits a few days it will start fine. If it sits about a week it take a long time to start, it's as if there is no gas in the carb. Suggestions please!

Thanks

Harry
38513

[Wayne Pope (722)]

Re: C2 - 63 WCFB

I don't know the cold idle speed. It is normal for carbs to dry out. You can crank and pump, prime with a syringe, or install an electric fuel pump.

[Eugene Bliley (13136)]

Re: C2 - 63 WCFB

Harry,
Per the 1963 Corvette Shop Manual (Section 6M)-Specifications 14-4 (Engine-Fuel, the Fast Idle Setting is 1750 RPM.

Make adjustment after engine is thoroughly warmed-up. Adjust with idle adjusting tang on high step of fast idle cam.

Extra info.: Curb idle is 475 RPM for standard shift models and 450 RPM for Automatic models with transmission in Drive range.

I cannot comment on your Question 2.

Good luck,
Gene

[Harry Sadlock]

Re: C2 - 63 WCFB

Gene, I must have looked at that section 10 times and never saw the number. I guess my mind didn't associate fast idle with the other sections on choke adjustment, oh well.

Thanks

Harry

[Michael Hanson (4067)]

Re: C2 - 63 WCFB

Harry,

The "no start" problem that you describe is common today. It is indeed caused by an empty carburetor bowl. This is a fairly new problem and getting worse as the newer formulas for fuel are causing the evaporation rate to go up, especially on hot engine shut down. It evaporates even faster as the percentage of ethanol is increased in the mix. I don't have any of the scientific info but maybe Duke can provide that. He knows 50 times more about petro products than I do and it could be an interesting discussion.

As Gene mentioned, make sure that the engine is at "normal operating temperature" when the fast idle speed is set. This is the only spec for this speed and no cold RPM spec exists. The cold RPM will be much different than this figure and will vary quite a bit depending on outside air temp. I don't think there is a cold engine fast idle RPM check in NCRS judging but if there is, it should be revised or eliminated. It's a spec that doesn't exist.

Michael

[Jim Trekell (22375)]

Re: C2 - 63 WCFB

Harry whenever I let my C3's with Holley carbs go without driving for couple weeks or longer I always use a syringe to inject fuel into the carb throttle body before trying to start them. They always fire right up.

[John Hinckley (29964)]

Re: C2 - 63 WCFB

I deal with this evaporation issue every spring after my toys have been in winter hibernation for six months (or if they sit for more than a couple of weeks during "driving season"); I just fill the primary float bowl through the bowl vent tube with a plastic syringe (takes 2-3 ounces to fill it), and they start instantly, without the extended cranking required if you let the fuel pump fill the bowl instead.

[Harry Sadlock]

Re: C2 - 63 WCFB

Thanks everyone!!

Harry