1969 427 won't start when cold

[Jonathan C.]

I hope you guys can give me some ideas. I'm just getting my feet wet learning about engines. I recently got my 427/400 rebuilt (30 over, new stock grind cam, new crank and pistons) by a reputable machine shop. I am currently running a '68 390 horse intake and remanufactured Q-Jet. I find myself nearly draining the battery everytime the car is cold. Once started the engine runs fine and even four hours later when its still somewhat warm it fires right up. When the choke is in the closed setting it won't fire at all. I have been propping the flap open with a sharpie to get it to fire but it is very difficult. I'll bet on average it takes ten pumps on the throttle and ten minutes of rrr-rrr-rrr before it will fire. Thanks in advance for your help.

Jonathan

[Verle R.]

Re: 1969 427 won't start when cold

Jonathan,

Many of the old Quadrajet carburetors leak gas out the bottom of the fuel bowl into the intake manifold so you do not see signs of a leak. If this is the problem, after the car sits for a while all the gas drains out of the carburetor and you must crank for some time to pump gas into the bowl. There may be sufficient gas in the intake to cause a flood situation inside the engine.

Your description suggests this problem.

The fix is to remove the carburetor, remove the base then clean and epoxy the two protrudences on the bottom of the bowl. They are originally plugged with lead (I think) but often develop leaks over the years.

Verle

[Clem Z.]

if the 69 has the fuel pump with the return line

to the fuel tank and the Q jet carb has a "windowed" needle seat you MUST use a fuel filter in the carb with a check valve because wihout the fuel level in the bowl will drop as the fuel runs back out thru the "window" in the needle seat. JMHO

[Joe L.]

Re: if the 69 has the fuel pump with the return li

clem------

1969 Corvettes did not originally use a fuel pump with the integral return line (i.e. "long cannister" type). Although all 1969 engines with Rochester carbs did use a fuel return line, the fuel return was from the GF-432 filter and not from the fuel pump, itself. 1970 was the first year for the long-cannister style fuel pump with integral fuel return. For 1970-81, this configuration pump was used for all engines except LT-1.

Of course, who knows what's on this car now. If someone has incorrectly installed a long cannister pump, then your suggestion might be exactly what the problem is here.

[Jonathan C.]

Re: 1969 427 won't start when cold

Thanks guys, I'm looking into this. I'll keep you updated.

Jonathan