1972 Beetle Loses Power at Sustained High Speed / RPMs

Hi all.

Bear with me, I'm brand new to this.

I have a 1972 Beetle that I recently bought. It has run perfectly
until a few days ago when it stalled on the freeway. I was eventually
able to limp home, and I replaced the fuel filter, which looked like it
might be clogging, and cleaned the screen in the fuel pump. It ran
fine the next day until I was driving home and got on the freeway
again; it died in the exact same spot. This time I could not start it
and had to tow it home.

I replaced the air filter and opened up checked the carburator, which
seemed to be in normal working order (nothing obviously wrong with it,
anyway, but this is the first time I've looked at one, so what do I
know?). At this point it would start, but stall after a couple miles
and need to cool down in order to start again.

Finally, I broke down and took it to a mechanic. He found a bad valve
and fixed it, claiming that was the cause of my problem. He also did a
general tune up, replaced the plugs and points, and replaced the
condenser, which he said was the wrong part. The car was running great
when I left there.

Unfortunately, within a minute or two of getting on the freeway, it
stalled again. It was definitely better than before, and I was able to
get off the freeway and drive normally on surface streets to my
destination.

Basically what happens is I get up to speed (around 65-75 MPH) and ease
off the gas, at which point the engine seems to misfire a bit and lose
power in spurts. I respond by giving it more gas, and it loses power
altogether, and the engine dies as soon as I take it out of gear.
After sitting for a few minutes, it starts again but runs rough and
quickly dies again when the RPMs get high.

It seems like a carburator problem to me, but I am at a loss as to how
to correct it. Any ideas or suggestions would be greatly appreciated.

Thanks,
lukas

wrote:

> Hi all.
>
> Bear with me, I'm brand new to this.
>
> I have a 1972 Beetle that I recently bought. It has run perfectly
> until a few days ago when it stalled on the freeway. I was eventually
> able to limp home, and I replaced the fuel filter, which looked like it
> might be clogging, and cleaned the screen in the fuel pump. It ran
> fine the next day until I was driving home and got on the freeway
> again; it died in the exact same spot. This time I could not start it
> and had to tow it home.
>
> I replaced the air filter and opened up checked the carburator, which
> seemed to be in normal working order (nothing obviously wrong with it,
> anyway, but this is the first time I've looked at one, so what do I
> know?). At this point it would start, but stall after a couple miles
> and need to cool down in order to start again.
>
> Finally, I broke down and took it to a mechanic. He found a bad valve
> and fixed it, claiming that was the cause of my problem. He also did a
> general tune up, replaced the plugs and points, and replaced the
> condenser, which he said was the wrong part. The car was running great
> when I left there.
>
> Unfortunately, within a minute or two of getting on the freeway, it
> stalled again. It was definitely better than before, and I was able to
> get off the freeway and drive normally on surface streets to my
> destination.
>
> Basically what happens is I get up to speed (around 65-75 MPH) and ease
> off the gas, at which point the engine seems to misfire a bit and lose
> power in spurts. I respond by giving it more gas, and it loses power
> altogether, and the engine dies as soon as I take it out of gear.
> After sitting for a few minutes, it starts again but runs rough and
> quickly dies again when the RPMs get high.
>
> It seems like a carburator problem to me, but I am at a loss as to how
> to correct it. Any ideas or suggestions would be greatly appreciated.
>
> Thanks,
> lukas
>



Could be overheating.
When it happens, does the engine seem hot? Can you pull the dipstick and
hold it in your bare hand while you check the oil level? Is there enough
oil? Are the engine bay tin and seals in good shape / in place? The
engine bay must be sealed, NO air must enter from under the car. Very
often there's tin pieces or seal missing, and the hot air from the
exhaust system rises up into the engine bay and finds it's way into the
fan... and hot air won't cool the engine enough.. the engine then starts
overheating, and thus producing even more hot air, and making itself run
even hotter... and soon this it will die.

Jan

wrote:
> Hi all.
>
> Bear with me, I'm brand new to this.
>
> I have a 1972 Beetle that I recently bought. It has run perfectly
> until a few days ago when it stalled on the freeway. I was eventually
> able to limp home, and I replaced the fuel filter, which looked like it
> might be clogging, and cleaned the screen in the fuel pump. It ran
> fine the next day until I was driving home and got on the freeway
> again; it died in the exact same spot. This time I could not start it
> and had to tow it home.
>
> I replaced the air filter and opened up checked the carburator, which
> seemed to be in normal working order (nothing obviously wrong with it,
> anyway, but this is the first time I've looked at one, so what do I
> know?). At this point it would start, but stall after a couple miles
> and need to cool down in order to start again.
>
> Finally, I broke down and took it to a mechanic. He found a bad valve
> and fixed it, claiming that was the cause of my problem. He also did a
> general tune up, replaced the plugs and points, and replaced the
> condenser, which he said was the wrong part. The car was running great
> when I left there.
>
> Unfortunately, within a minute or two of getting on the freeway, it
> stalled again. It was definitely better than before, and I was able to
> get off the freeway and drive normally on surface streets to my
> destination.
>
> Basically what happens is I get up to speed (around 65-75 MPH) and ease
> off the gas, at which point the engine seems to misfire a bit and lose
> power in spurts. I respond by giving it more gas, and it loses power
> altogether, and the engine dies as soon as I take it out of gear.
> After sitting for a few minutes, it starts again but runs rough and
> quickly dies again when the RPMs get high.
>
> It seems like a carburator problem to me, but I am at a loss as to how
> to correct it. Any ideas or suggestions would be greatly appreciated.
>
> Thanks,
> lukas
>

It does indeed sound like a fuel problem (but maybe not carb itself).

Troubleshooting this kind of problem is tough even for the experienced.

If it were mine, I would want to know if there is fuel in the carb bowl
when it dies. This will tell you where to go next and beats by a mile
the "let's change this part and see what happens next" approach.

You could also check to see if there is spark when it dies but this
does not produce as clear cut an answer.
------------------

How deep into this do you want to get?
It's possible to check the carb fuel level but there are dangers
involved with a hot engine.

You can observe the accelerator jet discharge as the throttle
opens and this will *sometimes* tell if the carb has fuel or not.

Some less direct approaches:
If this is a Standard Beetle, there is a mesh screen in the
fuel tank outlet. These get clogged after, say, 34 years. <g>
You can remove the screen but the tank needs to be near empty.
Possible to view the screen by taking the fuel gauge sender out.

Super Beetles don't have the screen but may have an in-line filter
under the tank.

Next, starvation can be caused by a tank that doesn't vent.
Easy test is to go for a drive with the filler cap loosened.

--------------

Well, this may point you in some of the directions I would take.

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

Wow, thanks for the quick response and the good advice. Sounds like I
might be in over my head, but I'm ready to get my hands dirty.

Jan, you might be onto something with the overheating. There's plenty
of oil in there, but it's probably way overdue for a change (I know, I
know). I have noticed it gets surprisingly hot (have the third-degree
burn on my calf from the exhaust pipe to prove it). I'll change the
oil and see if it helps. I will check the seal on the engine bay, too.

Jim, I did check the screen in the fuel pump and it is clear (wish I'd
talked to you first, I did it with a full tank and damn it was messy).
I'm not confident I can figure out how to check the fuel levels in the
carb, but I'll give it a shot. And I'll try loosening the filler cap
next time this happens.

I ordered the Muir book and the repair manual, so hopefully I'll be
less mystified after I do some reading ;-)

Thanks again. I'll let you know when I sort it out.

lukas

> wrote in message
ups.com...
> Hi all.
>
> Bear with me, I'm brand new to this.
>
> I have a 1972 Beetle that I recently bought. It has run perfectly
> until a few days ago when it stalled on the freeway. I was eventually
> able to limp home, and I replaced the fuel filter, which looked like it
> might be clogging, and cleaned the screen in the fuel pump. It ran
> fine the next day until I was driving home and got on the freeway
> again; it died in the exact same spot. This time I could not start it
> and had to tow it home.
>
> I replaced the air filter and opened up checked the carburator, which
> seemed to be in normal working order (nothing obviously wrong with it,
> anyway, but this is the first time I've looked at one, so what do I
> know?). At this point it would start, but stall after a couple miles
> and need to cool down in order to start again.
>
> Finally, I broke down and took it to a mechanic. He found a bad valve
> and fixed it, claiming that was the cause of my problem. He also did a
> general tune up, replaced the plugs and points, and replaced the
> condenser, which he said was the wrong part. The car was running great
> when I left there.
>
> Unfortunately, within a minute or two of getting on the freeway, it
> stalled again. It was definitely better than before, and I was able to
> get off the freeway and drive normally on surface streets to my
> destination.
>
> Basically what happens is I get up to speed (around 65-75 MPH) and ease
> off the gas, at which point the engine seems to misfire a bit and lose
> power in spurts. I respond by giving it more gas, and it loses power
> altogether, and the engine dies as soon as I take it out of gear.
> After sitting for a few minutes, it starts again but runs rough and
> quickly dies again when the RPMs get high.
>
> It seems like a carburator problem to me, but I am at a loss as to how
> to correct it. Any ideas or suggestions would be greatly appreciated.
>
> Thanks,
> lukas
>
Hopefully you have solved the problem by now. I suspect more fuel line crud
but don't overlook exhaust damage. If there is a blockage it will restrict
flow and cause overheating also. Similar to fuel starvation. Long shot, but
check it out also. -BaH

Good thing the mechanic replaced the condensor. I found out the hard way
just what a bad condensor could do. Drive a while, (15 to 20 min even) then
sputter and die... let it cool... drive a while.. sputter and die... didn't
know what it was... but the points were getting burnt too...
--
KWW
'65 Beetle (Jenny the IOC)
'64 Beetle (TBD the Blue Wave)
"Busahaulic" > wrote in message
...
>
> > wrote in message
> ups.com...
>> Hi all.
>>
>> Bear with me, I'm brand new to this.
>>
>> I have a 1972 Beetle that I recently bought. It has run perfectly
>> until a few days ago when it stalled on the freeway. I was eventually
>> able to limp home, and I replaced the fuel filter, which looked like it
>> might be clogging, and cleaned the screen in the fuel pump. It ran
>> fine the next day until I was driving home and got on the freeway
>> again; it died in the exact same spot. This time I could not start it
>> and had to tow it home.
>>
>> I replaced the air filter and opened up checked the carburator, which
>> seemed to be in normal working order (nothing obviously wrong with it,
>> anyway, but this is the first time I've looked at one, so what do I
>> know?). At this point it would start, but stall after a couple miles
>> and need to cool down in order to start again.
>>
>> Finally, I broke down and took it to a mechanic. He found a bad valve
>> and fixed it, claiming that was the cause of my problem. He also did a
>> general tune up, replaced the plugs and points, and replaced the
>> condenser, which he said was the wrong part. The car was running great
>> when I left there.
>>
>> Unfortunately, within a minute or two of getting on the freeway, it
>> stalled again. It was definitely better than before, and I was able to
>> get off the freeway and drive normally on surface streets to my
>> destination.
>>
>> Basically what happens is I get up to speed (around 65-75 MPH) and ease
>> off the gas, at which point the engine seems to misfire a bit and lose
>> power in spurts. I respond by giving it more gas, and it loses power
>> altogether, and the engine dies as soon as I take it out of gear.
>> After sitting for a few minutes, it starts again but runs rough and
>> quickly dies again when the RPMs get high.
>>
>> It seems like a carburator problem to me, but I am at a loss as to how
>> to correct it. Any ideas or suggestions would be greatly appreciated.
>>
>> Thanks,
>> lukas
>>
> Hopefully you have solved the problem by now. I suspect more fuel line
> crud
> but don't overlook exhaust damage. If there is a blockage it will restrict
> flow and cause overheating also. Similar to fuel starvation. Long shot,
> but
> check it out also. -BaH
>
>