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Post Info TOPIC: Inline 6 cold start issues


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Inline 6 cold start issues


Hi there.  I have had my 62 strato chief for a few weeks now. Ordered a bunch of interior bits from NOS today during their sale.   Seems like a good company. 

Anyway i am having an issue with cold start. 

When i got it, it had old gas in it and to start it i had to put gas in the carb to fire it up.  I have worked through most of that old gas and put in 15 liters fresh and it started without putting gas in carb. 

When i dont start the car in a number of days i have to pump the gas like ten times.  I havent started it now in about ten days and i pumped 10 times and tried starting to no avail.  I did this many times till the battery started going flat.  It did fire over and stalled a couple times.  So it does want to go.  When it is warm and has been running it fires up easy. 

Am i still having gas issues or is the spark perhaps not robust enough.  Should i change spark plugs and wires etc.

It is a 194 six cylinder with a single carb.

 

thanks

 



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A Poncho Legend!

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Next time it's cold, before you try starting it-

Remove the air cleaner.

While you are looking down the carburetor throat, manually pump the throttle linkage a couple of times. If you see a shot of gas each time you do that, you know the fuel bowl is staying full and also you know the accelerator pump in the carb is working.

My guess is you won't see a shot of fuel. It's likely either a bad accelerator pump or the fuel pump on the engine is allowing the fuel to drain back. I had a bad fuel pump that did that and it's very annoying having to crank and crank each time to get the carb bowl filled again.

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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles 

1966 Grande Parisienne, 396 1 of 23 factory air cars



Canadian Poncho Superstar!

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Another thing to check while doing what Carl Stevenson suggests is to ensure the choke plate is closing when the throttle linkage is operated.   Because of the slow cranking speed, the fuel/air mixture MUST be very rich.  The throttle plate should close (open maybe 1/8") to restrict the amount of air getting into the mixture - hence providing a rich mixture.

So it's a combination of ensuring the accelerator pump is providing shots of fuel, and the choke plate is closing to restrict the amount of air.



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70 2+2 convertible
70 2+2 hardtop
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Guru

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Another thing that can add to the problem is that summer gas is less volatile than the gas we get in the winter.
From what I've read it seems that it's the vapours in the gas that ignite first and winter gas has more of those "vapours" (I'm sure that's not the word they'd use to describe it but it's something like that)
I also gather that the vapours tend to evaporate over time and that makes old gas harder to light when it's cold.

This probably isn't the cause of your particular problem but a combination of older gas and summer blend gas might make it harder starting than normal.

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Barrie Ont.

409 powered 61 Poncho

best time 9.06@ 148 



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Thanks for the tips. It wasn't too cold in my garage maybe around zero. I do recall watching the fuel going into the bowl before and it didn't squirt forcefully like I have seen with other carbs. It just kind of pooled in there and disappeared pretty quickly.
I will check to see how the butterfly behaves in a few days. Getting hit with a cold snap and my garage will be around minus 10

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Canadian Poncho Superstar!

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I can't recall if your 62 has the original carb, but I recall that it has an engine swap to the 194. The original carb for a 62 six cylinder would be a Rochester BC. It actually has a leather plunger in it, real 1930s technology! The leather could be dried out and cracked. The choke is not a vacuum choke, rather a sort of coiled up bi-metal strip inside a round housing (1954 technology). The choke changed to the more conventional vacuum choke for 1963 and the carb was now known as the BV. The carb itself remained the same old vintage piece. They made them through 1967 before being replaced with a new Rochester Monojet.



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67 Chevelle Malibu Sport Coupe, Oshawa-built 250 PG never disturbed.

In garage, 296 cid inline six & TH350...

Cam, Toronto.


I don't judge a man by how far he's fallen, but by how far back he bounces - Patton



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good info here, i have the BV, vacuum is sucked from ontop of the manifold (hot air) through the black gadget on the side of the carb and that will actuate the choke... when the air gets hot it releases the choke...

is the monojet a better carb>?

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1962 4 door Canadian Laurentian, 261 cu.in 6 cyl, pwr glide



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CdnGMfan wrote:

I can't recall if your 62 has the original carb, but I recall that it has an engine swap to the 194. The original carb for a 62 six cylinder would be a Rochester BC. It actually has a leather plunger in it, real 1930s technology! The leather could be dried out and cracked. The choke is not a vacuum choke, rather a sort of coiled up bi-metal strip inside a round housing (1954 technology). The choke changed to the more conventional vacuum choke for 1963 and the carb was now known as the BV. The carb itself remained the same old vintage piece. They made them through 1967 before being replaced with a new Rochester Monojet.


 Cam, you never stop amazing me with your knowledge of all things GM. Cam, when is your book about all things GM coming out ? It is always very welcome to hear all this great information you share with the C.P. brotherhood. Cheers. George



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1957 Pontiac Pathfinder Deluxe sedan restored 261 six

1974 Chevrolet Caprice Estate wagon low mileage original 400 V-8



A Poncho Legend!

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I remember my 70 Biscayne had the bi-metal strip for a choke actuator. On really cold days you could hear it snap the choke plate shut from inside the car. I also remember how important it was to have the stove pipe from the manifold to the air cleaner working properly. Without it my 6 would pop and sputter when I tried to accelerate on cold days.


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Canadian Poncho Superstar!

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Canadian Poncho wrote:

I remember my 70 Biscayne had the bi-metal strip for a choke actuator. On really cold days you could hear it snap the choke plate shut from inside the car. I also remember how important it was to have the stove pipe from the manifold to the air cleaner working properly. Without it my 6 would pop and sputter when I tried to accelerate on cold days.


 Same technology on my 261 inline one barrel carb and it has always worked great. 



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1957 Pontiac Pathfinder Deluxe sedan restored 261 six

1974 Chevrolet Caprice Estate wagon low mileage original 400 V-8

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