Home » Public Forums » GMCnet » Twisted Fuel Line/JB Weld?
| Twisted Fuel Line/JB Weld? [message #357602] |
Sun, 09 August 2020 14:20  |
Greg C.
Messages: 224
Registered: October 2019
Location: Knoxville, TN
Karma: 0
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Senior Member |
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Today I tightened the AC compressor belt. A little easier than I thought it would be. Then I was going to change the carburetor filter.
Background, I drove the coach 1000 miles from Texas, the first day barely making headway because of engine hesitation/misfire due to water in the fuel. Eventually made it home, got the coach jacked up and found a clear plastic fuel filter in front of a Mr. Gasket electric fuel pump which was in front of the fuel selector valve. Said plastic fuel filter was half full of water.
Last week I drained both fuel tanks through the drain plugs into a pan. I had an old Dodge truck fuel pump mounted on a board with a Racor marine water/fuel separator filter. I pumped all the gas (20 gallons) through this filter into five gallon cans. After draining a little water out of the Racor, I pumped all the gas back through the Racor into the coach.
I removed the Mr. Gasket pump, cleaned out its prefilter, and tested it. Seems to work fine, but did not work on the coach. Ran down the power wire that was connected to it, and found that a PO had cut the wire. I installed a new fused circuit with a switch, and now it does work. I then drove it to a gas station and filled it up.
So the next thing on my list was to replace the carburetor fuel filter. But when I looked at it today, I could see that I was in trouble. If you look behind the copper gasket on the screw in filter housing, you will see what appears to be JB Weld. I know this particular problem is thoroughly documented in the forum and also how it happens. I've seen this happen myself to a Q Jet in the past.
[url=http://www.gmcmhphotos.com/photos/data/7320/medium/Twisted_fuel_line1.jpg] [url]
I am hoping that whoever boogered this up didn't go ahead and put a filter in there. The fuel line has been cut and rubber line installed along with a tee fitting, currently plugged up. Maybe a fuel pressure gauge was being used to diagnose a problem, I don't know.
So, what should I do here? I haven't tried to remove the fuel line fitting. I probably can do that, as it doesn't look cross threaded. I also took a picture of the carb serial number, so I can see if it is an original carb.
http://www.gmcmhphotos.com/photos/data/7320/Carb_Number.jpg
[url=http://www.gmcmhphotos.com/photos/data/7320/Carb_Number.jpg] [url]
Lastly, there is a vacuum line shown in this picture that is plugged. There is also what appears to be a thermostatically controlled vacuum port near it. Does this line go there? What does it do? Do I need to fix it?
[url=http://www.gmcmhphotos.com/photos/data/7320/medium/Mystery_vacuum_line.jpg] [url]
Thank you.
Greg Crawford
KM4ZCR
Knoxville, TN
"Ruby Sue"
1977 Royale
Rear Bath
403 Engine
American Eagle Wheels
Early Version Alex Sirum Quad bags
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| Re: [GMCnet] Twisted Fuel Line/JB Weld? [message #357607 is a reply to message #357602] |
Sun, 09 August 2020 16:29  |
bdub
Messages: 1578
Registered: February 2004
Location: Central Texas
Karma: 5
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Senior Member |
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I'd install one of Jim Bounds flexible hoses if I were you:
https://www.gmcrvparts.com/product-p/gm12-007.4.htm
A popular way to wire in that aux pump is from the positive side of the tank
selector valve. That way when you choose the auxiliary tank, the electric
pump comes on. (I suppose a day late for you)
Here's a list of carbs used on GMC Motorhomes
7043254 - 73 & 74, 455's
7045554 - 75 & 76, 455's Federal
7045254 Calif.
17057559 - 77 403's Federal
17057254 Calif. * I have one of these
17058559 - 78 403's Federal
17058254 Calif.
Your ported carb vacuum line seems to be terminated prior to the TVS.
That's the line to the left of the filter housing. It should to the TVS,
then another line go from that to the vacuum advance on the distributor. I
don't recognize that plugged port on the right side.
hth
bdub
76 Palm Beach
-----Original Message-----
From: Gmclist On Behalf Of Greg Crawford via Gmclist
Sent: Sunday, August 9, 2020 2:21 PM
Subject: [GMCnet] Twisted Fuel Line/JB Weld?
Today I tightened the AC compressor belt. A little easier than I thought it
would be. Then I was going to change the carburetor filter.
Background, I drove the coach 1000 miles from Texas, the first day barely
making headway because of engine hesitation/misfire due to water in the
fuel. Eventually made it home, got the coach jacked up and found a clear
plastic fuel filter in front of a Mr. Gasket electric fuel pump which was in
front of the fuel selector valve. Said plastic fuel filter was half full of
water.
Last week I drained both fuel tanks through the drain plugs into a pan. I
had an old Dodge truck fuel pump mounted on a board with a Racor marine
water/fuel separator filter. I pumped all the gas (20 gallons) through this
filter into five gallon cans. After draining a little water out of the
Racor, I pumped all the gas back through the Racor into the coach.
I removed the Mr. Gasket pump, cleaned out its prefilter, and tested it.
Seems to work fine, but did not work on the coach. Ran down the power wire
that was connected to it, and found that a PO had cut the wire. I installed
a new fused circuit with a switch, and now it does work. I then drove it
to a gas station and filled it up.
So the next thing on my list was to replace the carburetor fuel filter. But
when I looked at it today, I could see that I was in trouble. If you look
behind the copper gasket on the screw in filter housing, you will see what
appears to be JB Weld. I know this particular problem is thoroughly
documented in the forum and also how it happens. I've seen this happen
myself to a Q Jet in the past.
[url=http://www.gmcmhphotos.com/photos/data/7320/medium/Twisted_fuel_line1.j
pg][url]
I am hoping that whoever boogered this up didn't go ahead and put a filter
in there. The fuel line has been cut and rubber line installed along with a
tee fitting, currently plugged up. Maybe a fuel pressure gauge was being
used to diagnose a problem, I don't know.
So, what should I do here? I haven't tried to remove the fuel line fitting.
I probably can do that, as it doesn't look cross threaded. I also took a
picture of the carb serial number, so I can see if it is an original carb.
http://www.gmcmhphotos.com/photos/data/7320/Carb_Number.jpg
[url=http://www.gmcmhphotos.com/photos/data/7320/Carb_Number.jpg][url]
Lastly, there is a vacuum line shown in this picture that is plugged. There
is also what appears to be a thermostatically controlled vacuum port near
it. Does this line go there? What does it do? Do I need to fix it?
[url=http://www.gmcmhphotos.com/photos/data/7320/medium/Mystery_vacuum_line.
jpg][url]
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bdub
'76 Palm Beach/Central Texas
www.bdub.net
www.gmcmhphotos.com
www.gmcmotorhomemarketplace.com
www.gmcmhregistry.com
www.facebook.com/groups/classicgmcmotorhomes
www.facebook.com/groups/gmcmm
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| Re: [GMCnet] Twisted Fuel Line/JB Weld? [message #357608 is a reply to message #357607] |
Sun, 09 August 2020 16:44 |
Dolph Santorine
Messages: 1236
Registered: April 2011
Location: Wheeling, WV
Karma: -41
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Senior Member |
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Billy
In my experience, the TVS is usually stopped working about 1987, and eliminating it always seemed to be the better option.
My .02
Dolph Santorine
DE AD0LF
Wheeling, West Virginia
1977 ex-Palm Beach TZE167V100820
Howell EFI/EBL , Reaction Arms, Manny Transmission
> On Aug 9, 2020, at 5:30 PM, Billy Massey via Gmclist wrote:
>
> I'd install one of Jim Bounds flexible hoses if I were you:
> https://www.gmcrvparts.com/product-p/gm12-007.4.htm
>
> A popular way to wire in that aux pump is from the positive side of the tank
> selector valve. That way when you choose the auxiliary tank, the electric
> pump comes on. (I suppose a day late for you)
>
> Here's a list of carbs used on GMC Motorhomes
> 7043254 - 73 & 74, 455's
>
> 7045554 - 75 & 76, 455's Federal
> 7045254 Calif.
>
> 17057559 - 77 403's Federal
> 17057254 Calif. * I have one of these
>
> 17058559 - 78 403's Federal
> 17058254 Calif.
>
> Your ported carb vacuum line seems to be terminated prior to the TVS.
> That's the line to the left of the filter housing. It should to the TVS,
> then another line go from that to the vacuum advance on the distributor. I
> don't recognize that plugged port on the right side.
>
> hth
> bdub
> 76 Palm Beach
>
>
> -----Original Message-----
> From: Gmclist On Behalf Of Greg Crawford via Gmclist
> Sent: Sunday, August 9, 2020 2:21 PM
> Subject: [GMCnet] Twisted Fuel Line/JB Weld?
>
> Today I tightened the AC compressor belt. A little easier than I thought it
> would be. Then I was going to change the carburetor filter.
>
> Background, I drove the coach 1000 miles from Texas, the first day barely
> making headway because of engine hesitation/misfire due to water in the
> fuel. Eventually made it home, got the coach jacked up and found a clear
> plastic fuel filter in front of a Mr. Gasket electric fuel pump which was in
> front of the fuel selector valve. Said plastic fuel filter was half full of
> water.
>
> Last week I drained both fuel tanks through the drain plugs into a pan. I
> had an old Dodge truck fuel pump mounted on a board with a Racor marine
> water/fuel separator filter. I pumped all the gas (20 gallons) through this
> filter into five gallon cans. After draining a little water out of the
> Racor, I pumped all the gas back through the Racor into the coach.
> I removed the Mr. Gasket pump, cleaned out its prefilter, and tested it.
> Seems to work fine, but did not work on the coach. Ran down the power wire
> that was connected to it, and found that a PO had cut the wire. I installed
> a new fused circuit with a switch, and now it does work. I then drove it
> to a gas station and filled it up.
>
> So the next thing on my list was to replace the carburetor fuel filter. But
> when I looked at it today, I could see that I was in trouble. If you look
> behind the copper gasket on the screw in filter housing, you will see what
> appears to be JB Weld. I know this particular problem is thoroughly
> documented in the forum and also how it happens. I've seen this happen
> myself to a Q Jet in the past.
>
>
> [url=http://www.gmcmhphotos.com/photos/data/7320/medium/Twisted_fuel_line1.j
> pg][url]
>
>
> I am hoping that whoever boogered this up didn't go ahead and put a filter
> in there. The fuel line has been cut and rubber line installed along with a
> tee fitting, currently plugged up. Maybe a fuel pressure gauge was being
> used to diagnose a problem, I don't know.
>
> So, what should I do here? I haven't tried to remove the fuel line fitting.
> I probably can do that, as it doesn't look cross threaded. I also took a
> picture of the carb serial number, so I can see if it is an original carb.
>
>
> http://www.gmcmhphotos.com/photos/data/7320/Carb_Number.jpg
> [url=http://www.gmcmhphotos.com/photos/data/7320/Carb_Number.jpg][url]
>
>
>
> Lastly, there is a vacuum line shown in this picture that is plugged. There
> is also what appears to be a thermostatically controlled vacuum port near
> it. Does this line go there? What does it do? Do I need to fix it?
>
>
>
> [url=http://www.gmcmhphotos.com/photos/data/7320/medium/Mystery_vacuum_line.
> jpg][url]
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
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| Re: Twisted Fuel Line/JB Weld? [message #357612 is a reply to message #357602] |
Sun, 09 August 2020 20:48 |
C Boyd
Messages: 2629
Registered: April 2006
Karma: 18
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Senior Member |
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Greg, since you have a 1977 California 403, I would highly recommend reading up on what you got. There are extra parts and vacuum lines found only on your coach. There are suppose to be 2 TVS a low temp and a high temp, a throttle return control with vacuum activated electric solenoids working off the Drive position on the neutral safety switch with a added vacuum delay valve. Some distributors have 2 vacuum lines. This is truly a horse of a different color! You need to read up on this system to understand it before you jump in! It is designed to work with that carb. And it works beautifully.
Yes you need to replace the fuel line and change the filter in the housing. The filter acts also as a fuel pressure buffer to keep the pressure from surging under extreme conditions and possibly pushing fuel by the float needle and overfilling the fuel bowl. If the threads in the carb are ?? There are kits to replace the housing with one that is slightly oversized and self tapping. The gasket on the filter housing to carb is suppose to be nylon. Available at NAPA. Or I got one somewhere.
https://www.gmcmi.com/wp-content/uploads/2014/05/X7725_77-78-maint-manual-supp.pdf.
C. Boyd
76 Crestmont
East Tennessee
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| Re: Twisted Fuel Line/JB Weld? [message #357616 is a reply to message #357602] |
Mon, 10 August 2020 10:14 |
Greg C.
Messages: 224
Registered: October 2019
Location: Knoxville, TN
Karma: 0
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Senior Member |
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Thanks Chuck, John, and others for the reply.
So probably the best thing to do is replace the bad parts and try to get this system back to OEM specs. Is that the general consensus?
Where can I get the TVS (s)?
Yes, Chuck, I think I saw another TVS on the back of the intake manifold with no lines going to it. I currently have only one line running to the distributor, but I will download the vacuum line diagram for the California version so I can put everything back as factory.
Where can I get the filter housing repair kit?
Thanks again!
Greg Crawford
KM4ZCR
Knoxville, TN
"Ruby Sue"
1977 Royale
Rear Bath
403 Engine
American Eagle Wheels
Early Version Alex Sirum Quad bags
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| Re: Twisted Fuel Line/JB Weld? [message #357617 is a reply to message #357602] |
Mon, 10 August 2020 11:12 |
Greg C.
Messages: 224
Registered: October 2019
Location: Knoxville, TN
Karma: 0
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Senior Member |
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Okay. I just ordered the filter housing repair kit from Quadrajet Parts.
I will get out my parts manual and see if I can get a number for the two TVS's and take them to Oreilly's/NAPA/AZ.
Thanks again!
Greg Crawford
KM4ZCR
Knoxville, TN
"Ruby Sue"
1977 Royale
Rear Bath
403 Engine
American Eagle Wheels
Early Version Alex Sirum Quad bags
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| Re: Twisted Fuel Line/JB Weld? [message #357621 is a reply to message #357617] |
Mon, 10 August 2020 11:36 |
C Boyd
Messages: 2629
Registered: April 2006
Karma: 18
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Senior Member |
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Sir, the TVS’s might be good. Sometimes people unhook stuff they don’t understand and sometimes GM used the same type product for different reasons like the throttle return control is also used on other GM cars as an anti dieseling solenoid but is wired and plumbed different and acts different and does a different job. There is testing procedures in the supplement manual using a hand vacuum pump. I have one you can use.
Greg C. wrote on Mon, 10 August 2020 12:12Okay. I just ordered the filter housing repair kit from Quadrajet Parts.
I will get out my parts manual and see if I can get a number for the two TVS's and take them to Oreilly's/NAPA/AZ.
Thanks again!
C. Boyd
76 Crestmont
East Tennessee
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| Re: Twisted Fuel Line/JB Weld? [message #357628 is a reply to message #357602] |
Mon, 10 August 2020 19:21 |
Greg C.
Messages: 224
Registered: October 2019
Location: Knoxville, TN
Karma: 0
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Senior Member |
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Thanks Chuck. I have a small Mity Vac I can try.
Now that the left manifold has been replaced, I can hear the right one leaking. Hopefully, it's just the gasket!
Greg Crawford
KM4ZCR
Knoxville, TN
"Ruby Sue"
1977 Royale
Rear Bath
403 Engine
American Eagle Wheels
Early Version Alex Sirum Quad bags
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