Slow onset hesitation at speed

Okay. 1969 bone, stock, standard beetle would start up fine, run
well, accelerate well, even up hills. After 10 or so miles, a sort of
hesitation would creep in that felt like onset fuel starvation.
Checked fuel filter, found rust. Replaced filter. Checked fuel, tank-
found rust. Replaced fuel tank, cleaned brass filter where fuel line
screws into tank.

What else is there to check? What throws me is that the beetle runs
perfiectly for about the first ten miles or so and then gradually
develops signs of fuel starvation. It never stops running and seems
to idle fine.
David

Have you tried rebuilding your carburetor?

Also, check your intake manifold rubber boots. If they are cracked, they can
cause air to leak in and throw off your air & fuel mixture.


--
DAN MEDINA
"C7eca" > wrote in message
...
> Okay. 1969 bone, stock, standard beetle would start up fine, run
> well, accelerate well, even up hills. After 10 or so miles, a sort of
> hesitation would creep in that felt like onset fuel starvation.
> Checked fuel filter, found rust. Replaced filter. Checked fuel, tank-
> found rust. Replaced fuel tank, cleaned brass filter where fuel line
> screws into tank.
>
> What else is there to check? What throws me is that the beetle runs
> perfiectly for about the first ten miles or so and then gradually
> develops signs of fuel starvation. It never stops running and seems
> to idle fine.
> David

On Sep 7, 9:49*pm, "Funkie" > wrote:
> Have you tried rebuilding your carburetor?
>
> Also, check your intake manifold rubber boots. If they are cracked, they can
> cause air to leak in and throw off your air & fuel mixture.
>
> --
> DAN MEDINA"C7eca" > wrote in message
>
> ...
>
>
>
> > Okay. *1969 bone, stock, standard beetle would start up fine, run
> > well, accelerate well, even up hills. *After 10 or so miles, a sort of
> > hesitation would creep in that felt like onset fuel starvation.
> > Checked fuel filter, found rust. *Replaced filter. *Checked fuel, tank-
> > found rust. *Replaced fuel tank, cleaned brass filter where fuel line
> > screws into tank.
>
> > What else is there to check? *What throws me is that the beetle runs
> > perfiectly for about the first ten miles or so and then gradually
> > develops signs of fuel starvation. *It never stops running and seems
> > to idle fine.
> > David- Hide quoted text -
>
> - Show quoted text -

clean, or replace, the entire fuel line too.

C7eca wrote:
> Okay. 1969 bone, stock, standard beetle would start up fine, run
> well, accelerate well, even up hills. After 10 or so miles, a sort of
> hesitation would creep in that felt like onset fuel starvation.
> Checked fuel filter, found rust. Replaced filter. Checked fuel, tank-
> found rust. Replaced fuel tank, cleaned brass filter where fuel line
> screws into tank.
>
> What else is there to check? What throws me is that the beetle runs
> perfiectly for about the first ten miles or so and then gradually
> develops signs of fuel starvation. It never stops running and seems
> to idle fine.
> David


Can be hard to diagnose.

Before you replace any parts, try a couple of easy tests:

1) Make a hiway run with the filler cap loosened
(not with a full tank).
This will rule out/in a tank venting problem which can
produce the symptoms you describe.

2) Make some crude measurement of flow from the fuel line.
Disconnect the hose from the pump inlet. Run the hose into
some suitable container and watch the flow. If needed, jack
the car up to raise the tank.

If you get just a dribble, there is a clog. If there is a
steady stream which doesn't diminish over time, then the
system is good up to that point.

That could leave the pump as a suspect. For example,
one thing that can happen is for the pushrod to bind
in the bakelite stand as the engine heats up.

Speedy Jim
http://www.nls.net/mp/volks/

On Sep 8, 8:03�am, Speedy Jim > wrote:
> C7eca wrote:
> > Okay. �1969 bone, stock, standard beetle would start up fine, run
> > well, accelerate well, even up hills. �After 10 or so miles, a sort of
> > hesitation would creep in that felt like onset fuel starvation.
> > Checked fuel filter, found rust. �Replaced filter. �Checked fuel, tank-
> > found rust. �Replaced fuel tank, cleaned brass filter where fuel line
> > screws into tank.
>
> > What else is there to check? �What throws me is that the beetle runs
> > perfiectly for about the first ten miles or so and then gradually
> > develops signs of fuel starvation. �It never stops running and seems
> > to idle fine.
> > David
>
> Can be hard to diagnose.
>
> Before you replace any parts, try a couple of easy tests:
>
> 1) �Make a hiway run with the filler cap loosened
> (not with a full tank).
> This will rule out/in a tank venting problem which can
> produce the symptoms you describe.
>
> 2) �Make some crude measurement of flow from the fuel line.
> Disconnect the hose from the pump inlet. �Run the hose into
> some suitable container and watch the flow. �If needed, jack
> the car up to raise the tank.
>
> If you get just a dribble, there is a clog. �If there is a
> steady stream which doesn't diminish over time, �then the
> system is good up to that point.
>
> That could leave the pump as a suspect. �For example,
> one thing that can happen is for the pushrod to bind
> in the bakelite stand as the engine heats up.
>
> Speedy Jimhttp://www.nls.net/mp/volks/

Thanks everybody! I'll be working on this next good weekend.
David