Carb power piston spring

charles boyd

New member
Jul 8, 2007
3,462
2
0
I am having trouble finding the OEM power piston spring hg for the mh. I believe it is light, around 3 hg? The Edelbrock replacement carb I am
running starts and drives good but suffers from a very black tail pipe and 8 mpg. It has 5"hg springs in it and I am thinking it is going rich under
cruise conditions. Anyone have any ideas or suggestions?
--
C. Boyd
76 Crestmont
East Tennessee
 
Try Dick patterson

On Sat, Jun 30, 2018 at 7:08 PM Charles Boyd
wrote:

> I am having trouble finding the OEM power piston spring hg for the mh. I
> believe it is light, around 3 hg? The Edelbrock replacement carb I am
> running starts and drives good but suffers from a very black tail pipe and
> 8 mpg. It has 5"hg springs in it and I am thinking it is going rich under
> cruise conditions. Anyone have any ideas or suggestions?
> --
> C. Boyd
> 76 Crestmont
> East Tennessee
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
If I remember correctly Larry Weidner researched and ordered a bunch of them a little over 10 years ago. Try calling Larry to see if my memory is
correct.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
> If I remember correctly Larry Weidner researched and ordered a bunch of them a little over 10 years ago. Try calling Larry to see if my memory is
> correct.

Hey Ken,
Yup I did. But....that was about 10 years ago and have since switched to EFI, so got rid of most of the Carb stuff. I do recall that the correct
power valve spring is the "RED" one. It is designed to come in at about 8" of vacuum. Because of the weight that our engines have to carry, any
little rise or change in road elevation puts the vacuum to 9-10 in of vacuum having an effect on fuel mileage. The red spring will allow the primary
metering rods to begin lifting in the jets at 8", and the correct rods (can't remember what they are anymore) richen's things up pretty quick keeping
the combustion chamber cool. Just what I think I remember.

Best to contact Dick Patterson for correct spring and rods.
--
Larry
78 Royale w/500 Caddy
Menomonie, WI.
 
Cold I suggest getting hold of Cliff Ruggles. He wrote the latest book on
the Q-Jet. He's only 30 miles up the road from me, so I just drive up
when I need any thing. He's got a flock of parts and knowledge. Also a
really nice guy. I think I bought a bag with an assortment of power
piston springs the last time I was up.

Gary Kosier
77PB w/500Cad
Newark, Ohio

--------------------------------------------------
From: "Ken Burton"
Sent: Sunday, July 01, 2018 9:12 PM
To:
Subject: Re: [GMCnet] Carb power piston spring

> If I remember correctly Larry Weidner researched and ordered a bunch of
> them a little over 10 years ago. Try calling Larry to see if my memory is
> correct.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
You can heat the spring and let it air cool to weaken it.

Dont cut it and stretch it as some recommend. It actually makes it stiffer.

How much vac are you seeing at idle and low RPM cruise?

--
76 Glenbrook