low compression - running rich

I just bought a new-to-me 1970 beetle with a 1600SP engine from the original owner. It has always been a sea level car until I bought it. I live at a 7000 foot elevation.

The car has seemed to run ok when the weather was 50 degrees or higher but the plugs showed that it was running rich. Now that the temperature has fallen to below freezing, it seems to be running very rich to the point that it is fowling Bosch W8AC plugs. The compression is low ranging from 58 - 70 psi which would equate to 72 - 86 psi if taken at sea level.

I know the engine is getting tired but I don't want to rebuild it right now. I am currently looking out my window and it looks as though I am in the Sahara Desert during a sand storm but instead of sand, it is snow.

My question is would a hotter plug help? Do I have to rejet my Solex 30-PICT-3 carburetor? So far, I haven't taken it out of the city to actually use the main jet yet. I am using 85 octane gas because I felt it runs hotter than higher octane. Is my assumption correct?

Thanks in advance - Bob

Robert wrote:

> I just bought a new-to-me 1970 beetle with a 1600SP engine from the original owner. It has always been a sea level car until I bought it. I live at a 7000 foot elevation.
>
> The car has seemed to run ok when the weather was 50 degrees or higher but the plugs showed that it was running rich. Now that the temperature has fallen to below freezing, it seems to be running very rich to the point that it is fowling Bosch W8AC plugs. The compression is low ranging from 58 - 70 psi which would equate to 72 - 86 psi if taken at sea level.
>
> I know the engine is getting tired but I don't want to rebuild it right now. I am currently looking out my window and it looks as though I am in the Sahara Desert during a sand storm but instead of sand, it is snow.
>
> My question is would a hotter plug help? Do I have to rejet my Solex 30-PICT-3 carburetor? So far, I haven't taken it out of the city to actually use the main jet yet. I am using 85 octane gas because I felt it runs hotter than higher octane. Is my assumption correct?
>
> Thanks in advance - Bob
>

Low compression in all cyls. Hmmmmmmmmmm. Have you checked the
valve clearance yet? First step.

If the clearance is correct, the engine may be close to sucking in
a valve head and then you won't be able to rebuild it...ever.

If you're sure it's running rich, check that the float needle valve
closes tightly and that it's screwed in tightly.

One fix you can play around with is to add washers under the needle
valve. That will lower the fuel level in the bowl and reduce mixture.
(Shouldn't be necessary, but there you have it.) Or, change main jet
size.

http://www.vw-resource.com/carb.html#carburetor


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

Thanks for your reply. I did adjust the valves and only a couple were at
0.004" and the rest were at 0.006" so I made them all 0.006". I guess I can
just hope that it doesn't suck a valve. The engine was rebuilt in 1981 and
seems to run well other than fouling the plugs. The plugs become jet black.

I will change out the needle valve tomorrow with a known good one.

The web page you gave me is good so I will follow those instructions as
well.

Incidentally, my rear bearing replacement job went well, thanks for your
advise. - Bob


"Speedy Jim" > wrote in message
...
>
> Low compression in all cyls. Hmmmmmmmmmm. Have you checked the
> valve clearance yet? First step.
>
> If the clearance is correct, the engine may be close to sucking in
> a valve head and then you won't be able to rebuild it...ever.
>
> If you're sure it's running rich, check that the float needle valve
> closes tightly and that it's screwed in tightly.
>
> One fix you can play around with is to add washers under the needle
> valve. That will lower the fuel level in the bowl and reduce mixture.
> (Shouldn't be necessary, but there you have it.) Or, change main jet
> size.
>
> http://www.vw-resource.com/carb.html#carburetor
>
>
> Speedy Jim
> http://www.nls.net/mp/volks/

I have a H30/31 carb on a 1600DP with a pretty free flowing exhaust setup
and mild cam. It's on my buggy. I run at 4-6000' and it's running quite nice
on a 50idle and 125 main, 125air. You might even get by with a 50 idle and
120 main, which by the way, is what these H30/31's usually come jetted
with. These are the modern replacement for the carb you have and I believe
that is ballpark jetting for a1500SP.


RT
--
E-mail=fullname-at-telus.net


"Robert" > wrote in message
...
I just bought a new-to-me 1970 beetle with a 1600SP engine from the original
owner. It has always been a sea level car until I bought it. I live at a
7000 foot elevation.

The car has seemed to run ok when the weather was 50 degrees or higher but
the plugs showed that it was running rich. Now that the temperature has
fallen to below freezing, it seems to be running very rich to the point that
it is fowling Bosch W8AC plugs. The compression is low ranging from 58 - 70
psi which would equate to 72 - 86 psi if taken at sea level.

I know the engine is getting tired but I don't want to rebuild it right now.
I am currently looking out my window and it looks as though I am in the
Sahara Desert during a sand storm but instead of sand, it is snow.

My question is would a hotter plug help? Do I have to rejet my Solex
30-PICT-3 carburetor? So far, I haven't taken it out of the city to
actually use the main jet yet. I am using 85 octane gas because I felt it
runs hotter than higher octane. Is my assumption correct?

Thanks in advance - Bob

Engines will run rich at higher altitudes, due to the lower density air.
So, you could try fitting a smaller main jet and see what happens, as a
result. However, the low compression suggests that you may have more
serious problems to consider first.

"Robert" > wrote in message
...
I just bought a new-to-me 1970 beetle with a 1600SP engine from the original
owner. It has always been a sea level car until I bought it. I live at a
7000 foot elevation.

The car has seemed to run ok when the weather was 50 degrees or higher but
the plugs showed that it was running rich. Now that the temperature has
fallen to below freezing, it seems to be running very rich to the point that
it is fowling Bosch W8AC plugs. The compression is low ranging from 58 - 70
psi which would equate to 72 - 86 psi if taken at sea level.

I know the engine is getting tired but I don't want to rebuild it right now.
I am currently looking out my window and it looks as though I am in the
Sahara Desert during a sand storm but instead of sand, it is snow.

My question is would a hotter plug help? Do I have to rejet my Solex
30-PICT-3 carburetor? So far, I haven't taken it out of the city to
actually use the main jet yet. I am using 85 octane gas because I felt it
runs hotter than higher octane. Is my assumption correct?

Thanks in advance - Bob

I decided to pull the engine and the heads. Winter is a bad time to
mechanic but the risk verses the reward of not doing anything is to great.
Thanks for all your suggestions. - Bob

"Speedy Jim" > wrote in message
...
> Robert wrote:
>
>> I just bought a new-to-me 1970 beetle with a 1600SP engine from the
>> original owner. It has always been a sea level car until I bought it. I
>> live at a 7000 foot elevation.
>>
>> The car has seemed to run ok when the weather was 50 degrees or higher
>> but the plugs showed that it was running rich. Now that the temperature
>> has fallen to below freezing, it seems to be running very rich to the
>> point that it is fowling Bosch W8AC plugs. The compression is low
>> ranging from 58 - 70 psi which would equate to 72 - 86 psi if taken at
>> sea level.
>>
>> I know the engine is getting tired but I don't want to rebuild it right
>> now. I am currently looking out my window and it looks as though I am in
>> the Sahara Desert during a sand storm but instead of sand, it is snow.
>>
>> My question is would a hotter plug help? Do I have to rejet my Solex
>> 30-PICT-3 carburetor? So far, I haven't taken it out of the city to
>> actually use the main jet yet. I am using 85 octane gas because I felt
>> it runs hotter than higher octane. Is my assumption correct?
>>
>> Thanks in advance - Bob
>>
>
> Low compression in all cyls. Hmmmmmmmmmm. Have you checked the
> valve clearance yet? First step.
>
> If the clearance is correct, the engine may be close to sucking in
> a valve head and then you won't be able to rebuild it...ever.
>
> If you're sure it's running rich, check that the float needle valve
> closes tightly and that it's screwed in tightly.
>
> One fix you can play around with is to add washers under the needle
> valve. That will lower the fuel level in the bowl and reduce mixture.
> (Shouldn't be necessary, but there you have it.) Or, change main jet
> size.
>
> http://www.vw-resource.com/carb.html#carburetor
>
>
> Speedy Jim
> http://www.nls.net/mp/volks/

I decided to pull the engine and the heads. Winter is a bad time to
mechanic but the risk verses the reward of not doing anything is to great.
Thanks for all your suggestions. - Bob

"Speedy Jim" > wrote in message
...
> Robert wrote:
>
>> I just bought a new-to-me 1970 beetle with a 1600SP engine from the
>> original owner. It has always been a sea level car until I bought it. I
>> live at a 7000 foot elevation.
>>
>> The car has seemed to run ok when the weather was 50 degrees or higher
>> but the plugs showed that it was running rich. Now that the temperature
>> has fallen to below freezing, it seems to be running very rich to the
>> point that it is fowling Bosch W8AC plugs. The compression is low
>> ranging from 58 - 70 psi which would equate to 72 - 86 psi if taken at
>> sea level.
>>
>> I know the engine is getting tired but I don't want to rebuild it right
>> now. I am currently looking out my window and it looks as though I am in
>> the Sahara Desert during a sand storm but instead of sand, it is snow.
>>
>> My question is would a hotter plug help? Do I have to rejet my Solex
>> 30-PICT-3 carburetor? So far, I haven't taken it out of the city to
>> actually use the main jet yet. I am using 85 octane gas because I felt
>> it runs hotter than higher octane. Is my assumption correct?
>>
>> Thanks in advance - Bob
>>
>
> Low compression in all cyls. Hmmmmmmmmmm. Have you checked the
> valve clearance yet? First step.
>
> If the clearance is correct, the engine may be close to sucking in
> a valve head and then you won't be able to rebuild it...ever.
>
> If you're sure it's running rich, check that the float needle valve
> closes tightly and that it's screwed in tightly.
>
> One fix you can play around with is to add washers under the needle
> valve. That will lower the fuel level in the bowl and reduce mixture.
> (Shouldn't be necessary, but there you have it.) Or, change main jet
> size.
>
> http://www.vw-resource.com/carb.html#carburetor
>
>
> Speedy Jim
> http://www.nls.net/mp/volks/

It runs richer as the temp drops cause the choke is on which amplifies
any other problem area and if you let it idle to warm up, you can wash
the cylinders which fouls plugs and puts gas in the oil and lowers
compression and causes wear problems. Adjust your choke, check the
operation, warm air tube etc. Just my opinion of course. Been there,
done that.

href="http://albums.photo.epson.com/j/AlbumIndex?u=4025706&a=30209382&vt=vp">Den's
1977 Puma</a>

I took the heads of and noticed that the heat riser was blocked, #3 exhaust
valve was much lighter in color than all the rest and #2 spark plug hole was
almost completely stripped out. I ordered rebuilt heads and will put it
back together with a good intake manifold next week. thanks for everybody's
advise. - Bob

"Dennis Wik" > wrote in message
...
> It runs richer as the temp drops cause the choke is on which amplifies
> any other problem area and if you let it idle to warm up, you can wash
> the cylinders which fouls plugs and puts gas in the oil and lowers
> compression and causes wear problems. Adjust your choke, check the
> operation, warm air tube etc. Just my opinion of course. Been there,
> done that.
>
> href="http://albums.photo.epson.com/j/AlbumIndex?u=4025706&a=30209382&vt=vp">Den's
> 1977 Puma</a>
>