Anyone have a loose fuel pump?

[Matt Colie]

Along with so much else, I am putting on a new fuel pump.
(The other broke when the too small engine stand crashed.)

I am used to being able to hand pump an engine driven pump, and this new one, I cannot.
Well, with lots of leverage, I sort of can, but it is not what I am used to.

If you have one, new or old lying around, could you please pick it put and see if you can pump it by hand?

Thank you

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit

 

[LarryW]

When I first got started with my GMC, I removed the mechanical pump and put a plate over the hole. Then stuck a Carter 4070 in the line back at the
tanks. Never looked back. JWID
--
Larry
78 Royale w/500 Caddy
Menomonie, WI.

 

[Carl Stouffer]

Matt,

During my recent engine rebuild/replacement, I found the new fuel pump very stiff as well. I got a "Carter" mechanical pump off of Ebay, or Amazon,
can't remember which. I could barely move the lever. There is not much to hold onto on the pump end, but it seemed very stiff to me. I chalked it
up to getting older and weaker.
--
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles,
Solar battery charging. GMCSJ and GMCMI member

 

[Ken B]

I have one I removed from a 403 about 3 months ago. It is laying on the floor in my hangar. What do you need and how soon? I could drive up there
and check it out for you if necessary.

Ken B.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

 

[justin brady1]

Matt,
I noticed the exact same thing with a Carter replacement I put on mine. Way stiffer than I'm used to/expected.
It pumped fine after install. (other than vapro locking but we won't get into that can of worms :d )
--
Justin Brady
http://www.thegmcrv.com/
1976 Palm Beach 455

 

[tyler]

I took off a working pump and replaced it with a new one to diagnose a noise two years ago. No change, so presume the pump on my shelf was/is fine all
along. Could not budge it by hand just now
--
1975 Glenbrook, 1978 Royale rear bath
Raleigh, NC

 

[john r. lebetski]

Maybe they increased the spring load to keep them from sticking or to keep contact for the "racer" market?
--
John Lebetski
Woodstock, IL
77 Eleganza II

 

[Jim Hupy]

There are usually 2 springs in modern mechanical fuel pumps. One whose
purpose is to keep the operating lever in contact with the cam lube, is
quite strong. The other spring, which actually presses against the
diaphragm, is the one that actually pumps the fuel. It has about 3 - 5
pounds pressure. It is compressed by the movement of the operating lever,
and relaxes against the diaphragm. If there is an equal pressure against
the other side of the diaphram, like there would be when the carb needle
were closed, then that small spring does not move the diaphram and no
pumping takes place until the float needle opens. So, now you know how the
mechanical pump regulates fuel pressure.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

On Tue, May 22, 2018, 7:55 AM John R. Lebetski
wrote:

> Maybe they increased the spring load to keep them from sticking or to keep
> contact for the "racer" market?
> --
> John Lebetski
> Woodstock, IL
> 77 Eleganza II
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[Jim Hupy]

Darn spell check. Should be cam lobe, not lube.
Jim Hupy

> There are usually 2 springs in modern mechanical fuel pumps. One whose
> purpose is to keep the operating lever in contact with the cam lube, is
> quite strong. The other spring, which actually presses against the
> diaphragm, is the one that actually pumps the fuel. It has about 3 - 5
> pounds pressure. It is compressed by the movement of the operating lever,
> and relaxes against the diaphragm. If there is an equal pressure against
> the other side of the diaphram, like there would be when the carb needle
> were closed, then that small spring does not move the diaphram and no
> pumping takes place until the float needle opens. So, now you know how the
> mechanical pump regulates fuel pressure.
> Jim Hupy
> Salem, Or
> 78 GMC ROYALE 403
>
> On Tue, May 22, 2018, 7:55 AM John R. Lebetski

>
>> Maybe they increased the spring load to keep them from sticking or to
>> keep contact for the "racer" market?
>> --
>> John Lebetski
>> Woodstock, IL
>> 77 Eleganza II
>>
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>

 

[sgltrac]

Another nugget of learning thanks to the GMC net.

Sully
77 eleganza 2
Bellevue.

> Darn spell check. Should be cam lobe, not lube.
> Jim Hupy
>

>
> > There are usually 2 springs in modern mechanical fuel pumps. One whose
> > purpose is to keep the operating lever in contact with the cam lube, is
> > quite strong. The other spring, which actually presses against the
> > diaphragm, is the one that actually pumps the fuel. It has about 3 - 5
> > pounds pressure. It is compressed by the movement of the operating lever,
> > and relaxes against the diaphragm. If there is an equal pressure against
> > the other side of the diaphram, like there would be when the carb needle
> > were closed, then that small spring does not move the diaphram and no
> > pumping takes place until the float needle opens. So, now you know how
> the
> > mechanical pump regulates fuel pressure.
> > Jim Hupy
> > Salem, Or
> > 78 GMC ROYALE 403
> >
> > On Tue, May 22, 2018, 7:55 AM John R. Lebetski

> >
> >> Maybe they increased the spring load to keep them from sticking or to
> >> keep contact for the "racer" market?
> >> --
> >> John Lebetski
> >> Woodstock, IL
> >> 77 Eleganza II
> >>
> >>
> >> _______________________________________________
> >> GMCnet mailing list
> >> Unsubscribe or Change List Options:
> >> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >>
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
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[d c *mac* macdonald]

Leave "SPELL CHECK" on but turn "AUTO CORRECT" off!

D C "Mac" Macdonald​
Amateur Radio K2GKK​
Since 30 November '53​
USAF and FAA, Retired​
Member GMCMI & Classics​
Oklahoma City, OK​
"The Money Pit"​
TZE166V101966​
'76 ex-Palm Beach ​
k2gkk + hotmail dot com​

________________________________
From: Gmclist on behalf of James Hupy
Sent: Tuesday, May 22, 2018 10:14
To: gmclist
Subject: Re: [GMCnet] Anyone have a loose fuel pump?

Darn spell check. Should be cam lobe, not lube.
Jim Hupy

> There are usually 2 springs in modern mechanical fuel pumps. One whose
> purpose is to keep the operating lever in contact with the cam lube, is
> quite strong. The other spring, which actually presses against the
> diaphragm, is the one that actually pumps the fuel. It has about 3 - 5
> pounds pressure. It is compressed by the movement of the operating lever,
> and relaxes against the diaphragm. If there is an equal pressure against
> the other side of the diaphram, like there would be when the carb needle
> were closed, then that small spring does not move the diaphram and no
> pumping takes place until the float needle opens. So, now you know how the
> mechanical pump regulates fuel pressure.
> Jim Hupy
> Salem, Or
> 78 GMC ROYALE 403
>
> On Tue, May 22, 2018, 7:55 AM John R. Lebetski

>
>> Maybe they increased the spring load to keep them from sticking or to
>> keep contact for the "racer" market?
>> --
>> John Lebetski
>> Woodstock, IL
>> 77 Eleganza II
>>
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
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>>
>
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[lw8000]

Matt,
I too replaced our fuel pump twice in the past 4 years while diagnosing fuel issues... with a brand new Carter in each case, and noticed the same
thing. Apparently it's normal. Not a single problem with them (knock on wood).
--
Chris S. -
77 Kingsley, 3.70 FD, mostly OEM -
S.E. Michigan