Running real Rich - Need Help

[richard d smith]

Hi GMC'rs

My 76 Glenbrook is belching black stuff out the exhaust, the sparkers are
real black and it does not pull real hard any more.

This just started after I replaced all the Carb gaskets, to fix a vacuum
leak ( big hole in large bottom gasket), to fix transmission shifting
problem and others. Just replaced the gaskets and the inlet valve, made no
adjustments. All the jets are stock size and look tobe in good condition
(should be just about right for 5-6k feet). The choke is now adjusted so
that it Never comes on. Have had it apart a couple of times to check that
the rods are in the proper jet holes. The idle adjustment screws are at
about 4 turns, but it appears to run rich at all rpms. I have looked into
the carb when running and see no excess gas flowing. It starts when cold
just like the choke is adjusted perfectly.

Any help or clues will be very much appreciated !!!!!!

Rich - 76 Glenbrook
At the Castle in Colorado (Cloudy and raining much of the day)

 

[emerystora]

>Hi GMC'rs
>
>My 76 Glenbrook is belching black stuff out the exhaust, the sparkers are
>real black and it does not pull real hard any more.
>
>This just started after I replaced all the Carb gaskets, to fix a vacuum
>leak ( big hole in large bottom gasket), to fix transmission shifting
>problem and others. Just replaced the gaskets and the inlet valve, made no
>adjustments. All the jets are stock size and look tobe in good condition
>(should be just about right for 5-6k feet). The choke is now adjusted so
>that it Never comes on. Have had it apart a couple of times to check that
>the rods are in the proper jet holes. The idle adjustment screws are at
>about 4 turns, but it appears to run rich at all rpms. I have looked into
>the carb when running and see no excess gas flowing. It starts when cold
>just like the choke is adjusted perfectly.
>
>Any help or clues will be very much appreciated !!!!!!
>
>Rich - 76 Glenbrook
>At the Castle in Colorado (Cloudy and raining much of the day)

Well - it certainly is tellling you that it is running rich. Maybe
your float is sticking and leaking additional fuel into the carb, or
your butterfly valves are sticking and blocking some of the air flow,
or your secondaries are not functioning properly. Also check your
timing.

Another thing -- some carb kits have different holes in the gaskets
and you might be blocking a port (hole) with a gasket. If you still
have your old gaskets you may want to take the carb apart and double
check to see that the gaskets are exactly identical.

Emery Stora
77 Kingsley
Santa Fe, NM

 

[gene]

Have you rechecked the timing ??

gene

>Hi GMC'rs
>
>My 76 Glenbrook is belching black stuff out the exhaust, the sparkers are
>real black and it does not pull real hard any more.
>
>This just started after I replaced all the Carb gaskets, to fix a vacuum
>leak ( big hole in large bottom gasket), to fix transmission shifting
>problem and others. Just replaced the gaskets and the inlet valve, made no
>adjustments. All the jets are stock size and look tobe in good condition
>(should be just about right for 5-6k feet). The choke is now adjusted so
>that it Never comes on. Have had it apart a couple of times to check that
>the rods are in the proper jet holes. The idle adjustment screws are at
>about 4 turns, but it appears to run rich at all rpms. I have looked into
>the carb when running and see no excess gas flowing. It starts when cold
>just like the choke is adjusted perfectly.
>
>Any help or clues will be very much appreciated !!!!!!
>
>Rich - 76 Glenbrook
>At the Castle in Colorado (Cloudy and raining much of the day)
>
>
Genef -- 77PB/ore/ca
GMC MOTORHOME INFORMATION
mr.erf
http://www.california.com/~eagle/

 

[gene]

If the booster pump failed, it would not make it rich.... when my electric
fuel booster pump failed, I never knew it until I started getting that old
feeling, vapor lock, stalling at stop signs,etc. This was at high altitude
and high temps. When I replaced the pump the symptoms went away and I was
running again.

gene

>In a message dated 6/26/00 9:39:33 PM Central Daylight Time,

>
> your float is sticking and leaking additional fuel into the carb >>
>
>I wonder sometimes if the aux fuel pumps we all seem to have installed don't
>contribute to this problem. My theory is that these pumps get installed
>"in-line" with the mech pump. If there is a switch installed (like mine) and
>the switch is "off" then the mech pump has to not only pull the fuel through
>the OEM fuel route, but also through the pump, which, if it is like mine
>(carter) does offer some additional resistance. Before my next trip in a few
>weeks, I am going to finally install the NAPA pump with the bi-pass, which
>may solve my problem. I think the carter is pushing to much fuel into the
>carb. Just my thoughts.
>
>Larry Nelson
>Springfield, MO
>GMC 1975 Palm Beach
>WB0JOT
>
Genef -- 77PB/ore/ca
GMC MOTORHOME INFORMATION
mr.erf
http://www.california.com/~eagle/

 

[jim white]

make sure the needle is attached to the float correctly..

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> -----Original Message-----
> From: owner-gmcmotorhome
> [mailtowner-gmcmotorhome]On Behalf Of Richard D Smith
> Sent: Monday, June 26, 2000 8:40 PM
> To: gmcmotorhome
> Subject: RE: GMC: Running real Rich - Need Help
>
>
> Hi GMC'rs
>
> My 76 Glenbrook is belching black stuff out the exhaust, the sparkers are
> real black and it does not pull real hard any more.
>
> This just started after I replaced all the Carb gaskets, to fix a vacuum
> leak ( big hole in large bottom gasket), to fix transmission shifting
> problem and others. Just replaced the gaskets and the inlet
> valve, made no
> adjustments. All the jets are stock size and look tobe in good condition
> (should be just about right for 5-6k feet). The choke is now adjusted so
> that it Never comes on. Have had it apart a couple of times to check that
> the rods are in the proper jet holes. The idle adjustment screws are at
> about 4 turns, but it appears to run rich at all rpms. I have looked into
> the carb when running and see no excess gas flowing. It starts when cold
> just like the choke is adjusted perfectly.
>
> Any help or clues will be very much appreciated !!!!!!
>
> Rich - 76 Glenbrook
> At the Castle in Colorado (Cloudy and raining much of the day)
>

 

[ritch hwang]

>Hi GMC'rs
>
>My 76 Glenbrook is belching black stuff out the exhaust, the sparkers are
>real black and it does not pull real hard any more.
>
(snip)....

In addition to all of the suggestions posted so far re carb running rich,
IIRC the plugs at the bottom of the fuel bowls are also prone to leaking,
which a little epoxy should take care of. Good luck.

HTH,
Ritch, 76 Birch