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Mike S.
Mike S., Classic Car Mechanic
Category: Classic Car
Satisfied Customers: 6809
Experience:  A.S.E. certified with 25+ years experience.
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70 442 455 after about 10minutes of driving apon

Customer Question

70 442 455 after about 10minutes of driving apon deceleration and turning the engine starts to stall out and die.when trying to start again will hot it will not fire and gas belches back out of the carb and smokes abit ???
Submitted: 5 months ago.
Category: Classic Car
Expert:  Mike S. replied 5 months ago.

It sounds like you may have a blown head gasket.

Does the engine misfire while just setting there in park idling or while reving it up in park?

Customer: replied 5 months ago.
no this has happened twice now. after the first time it stalled out. we removed the carb and changed out the accelerator pump.worked for 2 short runs to a local cruise night about 5mins from my place. but on the longer run say 15 min when decelerating and turning a corner with the foot off the gas it starts to stumble and the when you step on it again it stalls like its not gets spark because its getting gas when it stalls out and belches out of the carb its probably the gas landing on they intake that smokes abiy
Customer: replied 5 months ago.
it has a plug and play MSD Distributer with Pertronics Flame thrower coil both have been in the car for about 10yr+
Expert:  Mike S. replied 5 months ago.

The accelerator pump is only for when you punch the throttle, it squirts gas down into the carb bore, for acceleration, hence the name. It has nothing to do with deceleration, and usually you only notice that it is bad when punching the gas pedal you get a hesitation.

Expert:  Mike S. replied 5 months ago.

So explain to me again exactly what the symptoms are.

Expert:  Mike S. replied 5 months ago.

Does this have a vacuum advance in the distributor cause hesitation can also be caused when that goes bad.

Expert:  Mike S. replied 5 months ago.

How is the base idle? Does the engine idle ok? Is the choke fully open after the engine is warm?

The stalling while foot off the gas and turning could be due to a base idle that is too low.

Customer: replied 5 months ago.
when I start the car and its cold everything was working fine. after a 10 min run. or warm up.when you take the your foot off the throttle to slow down and turn the car tends to hesitate and as soon as you give it a little throttle it sputters and then stalls like its not getting fuel only when it finally quits fuel spurts out of the carb
Customer: replied 5 months ago.
we didn't change any of the settings when we replaced the accelerator pump when we first had the issue with no fuel
Expert:  Mike S. replied 5 months ago.

Does the choke fully open after the engine is warmed up?

Customer: replied 5 months ago.
base idle is fine and choke settings, but problem only occurs after about 10 minutes of running time and when i take my foot off the throttle to stop
Expert:  Mike S. replied 5 months ago.

Make sure you are not dripping gasoline down the throttle bores. Grab a flashlight and a mirror, so it don't backfire in your face and look right down the throttle bores while the engine is idling and look to see if any gas is dripping onto either or both front throttle plates.

Customer: replied 5 months ago.
we also tried another carb from a running 400. It did the same thing because the engine was still hot and when we tried to start it.It started to coff and sputter and stall
Customer: replied 5 months ago.
we then put that carb back on the 400 and it started up and ran fine
Expert:  Mike S. replied 5 months ago.

Ok, let's start with the basics, what is the base timing set at, what is the base idle rpm, what is the amount of intake manifold vacuum at idle?

Expert:  Mike S. replied 5 months ago.

I suppose you shouldn't have to answer the base idle question since the other carb was the same but it would be ok to answer anyhow, just so I know.

Expert:  Mike S. replied 5 months ago.

When it spits out the carb, you said it's gasoline and smoke. Is it like a white mist? If so, that indicates a possible timing chain problem and either it's very loose or it is loose worn enough that it jumped but I doubt if it jumped because it would run poorly.

A good way to check if it's worn is to hook up a timing light, rev up the engine to when the timing in the distributor stops advancing, probably around 2,000 rpm, now rev it up an additional 1,000 rpm, so to 3,000 pm and then back and forth between 2,000 and 3,000 rpm and watch that timing mark. This throws the slack in the timing chain from one side to the other and if the timing mark moves more than 1/2" like this this most likely indicates that the timing chain is worn out.

Customer: replied 5 months ago.
Im sorry mike I don't think we are getting anywhere with this as we have done nothing with the base adjustments.The car gave me no problems till the accelerater pump issue witch was fixed.and doesn't explain why it still does it with the other carb.So instead of wasting your time and mine i don't think I'm getting any answers to my problem .So the deposit is as far as i can go. Thanks for now.Theres only 15000 miles on this motor as it was totally rebuilt
Expert:  Mike S. replied 5 months ago.

ok, sorry.

Customer: replied 5 months ago.
hi mike. sorry that i couldn't get what i wanted to hear from you.but since i was not satisfied with what you had to offer am i entitled to refund not the full but the remaining 35.00. Thanks

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