Adam Rodnitzky wrote:
>
> Hi all,
>
> My '70 Mk3 (single ZS carb) has a strange,
> intermittent problem that is baffling (and frustrating
> and stranding) me.
>
> At random intervals, the car will seemingly lose all
> fuel delivery to the carb. I'll be driving along, and
> suddenly the engine will die. If I have momentum, I
> keep the ignition on and the gas pedal floored while
> rolling along in gear and after 5-10 seconds the car
> will sputter a bit, then catch, sputter, then catch
> and spring back to life and be fine for another 10,
> 50, 100 or more miles.
>
> If I don't have momentum, the car grinds to a halt,
> and I either call the tow truck, or do the following:
> I spray starter fluid into the carb, which gets the
> engine to catch, suggesting it is not an ignition
> fault. Usually, after a minute or so of the
> spray/start/catch/die cycle, it'll start and run well
> for another 10/50/100 miles. I also have a clear glass
> fuel filter that goes on the line from the fuel pump
> to the carb (supplemented by a fuel filter directly
> out of the gas tank) and it shows the usual amount of
> fuel in the lines when the problem occurs. It does
> seem like it happens more often when there is less
> than 3/4 tank of gas (but that is conjecture).
>
> I rebuilt the carb a year and a half ago (along with
> the ignition system and a new fuel pump), replaced the
> fuel filters and adjusted the valves. I do know that
> the mixture is out of whack.
>
> Any suggestions before this happens to me on the
> Golden Gate Bridge ;)?
>
> Thanks!
>
> Adam
> '70 Spit Mk3
> '94 Alfa Romeo 164LS (for sale...)
> SF, CA USA
Adam,
You may have a problem with a vacuum developing in the fuel tank. Next
time it happens, open the tank cap and see if air suddenly rushes in and
the car will then start (after the float tank fills up. If your car has
a carbon filter that is connected to the tank vent, it may be clogged
up. If that is not the case, check your float bowl for accumulation of
brown crud. You might need to flush your tank and lines and have the
tank coated in the inside to keep down the accumulation of sediment.
Regards,
Joe
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