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How Many Cranks Til Your Mach Starts?
#21
The carb is new as of a year and a half ago. Holley 770 street avenger. I originally thought it might not be getting gas, but I'm pretty sure it squirts just fine when you twist the throttle. I'll go back and check when I get a chance. It does sit for up to a month between starts sometimes, but once you get it started it runs pretty good. Choke sets just fine. Like I said, I just assumed it was the oil running down from the rings and not being able to supply vacuum to draw the gas from the carb, but that's just my gut. Got nothing to support it. I should probably do a compression check. It's possible the block is original. I've always been able to get it started so I haven't really dug into it.

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#22
(06-18-2019, 08:06 PM)Don C Wrote: What carburetor? Ford and Holley carburetors often have leaking power valves that drain the fuel bowls. You may still have one shot of fuel left in the accelerator pump.

Is your choke functioning and adjusted?

You can add a little fuel through the fuel bowl vents, see if that gets it running.

+1 on the choke.  Happened to me.
Car would crank and crank.  Remove air cleaner
and put finger on choke, Bam.
Same with fuel bowls, seems like gas drains back
to pump after sitting for a while.  I have a Holley
770 Avenger.  An electric pump would fix that.
Occasionally if I dare to pump the gas after cranking
for a while, backfire.  Exhaust system is new patterned
after the one used on the Boss 351, it is loud.

mike
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#23
Empty fuel bowls would make sense. Thanks for the feedback.

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#24
Because the fuel enters at the top of the fuel bowl there isn't a way for the fuel to siphon back into the fuel line. The only way is out of the bottom of the carburetor, either into or onto the intake manifold.

I believe all newer Holleys have the antibackfire check valve to help preserve the enrichment valve, but they can still leak, either faulty construction, bad gasket (often overtightened), or too many dried-out cycles. And, don't forget porous castings.



“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
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#25
The typical 4150/4160 Holley has a habit of leaking out the accelerator pump diaphragm, which is at the bottom of the float bowls. You should see puddles of gas or some staining if it's leaking there. Fairly easy fix and only a couple dollars in parts.

As far as the OP, mine is four kicks of the pedal and it lights off in maybe 2 seconds of cranking. Current carb has a manual choke, which I have wired open. I high idle it for 10 seconds or so with my foot during warmer months and it'll stay running. If it's cold, it takes a little longer to idle by itself.


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#26
Set the choke, one crank. When warm, barely one crank, starts right up.

1969 Acapulco Blue Convertible
     408C CJ, 5 Spd
1973 Lava Red Mach 1
     Being restored - 351C, 4V, AOD
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#27
When mine was running , one or two seconds when cold, after setting the choke. When warm, first cylinder that had a spark. When hot, three seconds max, I have a high-torque geared starter.

I hate having an engine that won't start quickly. My wife and I had a motorhome on a Dodge van chassis, with a 400, that about drove me nuts. It was bad on both ends, cold blooded and hard to start when hot. When it would set, after warming up, the heat had no place to escape to. The fuel line between the fuel pump and carburetor would get hot, fuel expand, and flood the carburetor, too much pressure for the float valve. I ran a return line from a tee between the pump and carburetor, with a 0.03" orifice to the return line. That helped the hot start considerably. A lot of tinkering and adjusting got it to run better when cold, but never great. It just didn't want to move when it was cold.



“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
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