Part #. for carb filter? and, do i need it?

D

dave silva

New member
Oct 2, 2009
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Coach sat for a few years. I've drained the tanks but a new fuel filter clogged after 30 miles or so.

It has cartridge filter system up front instead of the inline. Makes it very easy to change filters.

Can i remove the carb filter until i get this worker out?

--
Dave & Ellen Silva
Hertford, NC

74 Birchaven, 1-ton and other stuff
 
Sir, my recommendation is to leave the filter in the carb. I believe it is a finer filter than the inline versions and will trap stuff that will clog
up carb passages. I also believe it buffers the pulse of the fuel pump for a more even flow thru the float needle. Always use a 1” back up wrench
to hold the housing as it is easy to cross thread and strip the threads and a 5/8 line wrench to keep from rounding off the fuel line.

> Coach sat for a few years. I've drained the tanks but a new fuel filter clogged after 30 miles or so.
>
> It has cartridge filter system up front instead of the inline. Makes it very easy to change filters.
>
> Can i remove the carb filter until i get this worked out?
>
> I'm gonna' need a few, what is the part number? - 74 Birch with 455

--
C. Boyd
76 Crestmont
East Tennessee
 
The filter in the Q-jet is a Wix 33048. I agree with Chuck, above. Keep one in there, at least until you have the tank problem worked out. It is a
finer filter and is your last line of defense against fine particles in your carburetor. Maybe after you start getting a clean element in your
cartridge filter, you might be able to do away with the carb filter, but it's probably still a good idea to continue running it.

Be VERY careful threading the housing into the carburetor. It is easy to strip and/or stretch the threads in the carb. You can also get the little
nylon gasket for the filter housing at better auto parts stores. Look for a guy with some gray in his beard at a NAPA or similar store. The young
guys at O'Reilly's generally will not have a clue about carb parts.
--
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
 
I'm all for keeping that filter as it is the final to protect the
carburetor.
I have run the same type of carburetors on our cars and trucks when we had
the carburetors.
Yes, I have ran it without and paid the price.later.
Just because you ran it without it without problem , don't think it works
that way most of the time.
Particulates come off your rubber hose and rusting steel line and rubber
diaphragm fuel pump.
Factory people are no idiots and know more than us .

On Mon, Dec 21, 2020 at 5:45 AM Carl Stouffer via Gmclist <

> The filter in the Q-jet is a Wix 33048. I agree with Chuck, above. Keep
> one in there, at least until you have the tank problem worked out. It is a
> finer filter and is your last line of defense against fine particles in
> your carburetor. Maybe after you start getting a clean element in your
> cartridge filter, you might be able to do away with the carb filter, but
> it's probably still a good idea to continue running it.
>
> Be VERY careful threading the housing into the carburetor. It is easy to
> strip and/or stretch the threads in the carb. You can also get the little
> nylon gasket for the filter housing at better auto parts stores. Look for
> a guy with some gray in his beard at a NAPA or similar store. The young
> guys at O'Reilly's generally will not have a clue about carb parts.
> --
> 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
>
> _______________________________________________
> 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.gmcrvparts.com
1-800-752-7502
 
THanks. i ordered a couple carb filters and several regular fuel filters. I believe the tanks were refreshed during the rahab and it sat with full
tanks all this time so i am hoping to clear the debris without having to do anything heroic.
--
Dave & Ellen Silva
Hertford, NC

74 Birchaven, 1-ton and other stuff
 
Dave,

Please take to heart the cautions about the thread in the carburetor body. This is easily damaged and I have witness this more than a few times.

When I change that filter (I carry them in spares), first I put a wrench on the 1" at the carburetor filter carrier and loosen the fuel line. The
metal fuel line will not want to come clear away on a stock 455. You can run the line nut back.
Then, I loosen the 1" filter carrier.
Then, I remove the four screws that hold the carburetor to the manifold. Mine has enough slack in the rubber vacuum lines to move the carburetor so
the metal fuel line can be clear.
Then, I back out the filter carrier and change the filter. Be sure to note that the open end of the filter goes into the carrier. There may or may
not be a spring and a special washer at the other end of the filter. This seems to be model and year dependent.
Now, screw the filter carrier back in with fingers only. If it does not spin down to the seat with figures only, try again.
*** This is a very fine thread and it is easily crossed and damaged. When it is, the carburetor body is junk. ***
With the filter carrier home, slide the carburetor back to where you can start the metal line back on its fitting.
Put the four screws back in the carburetor and snug them down. If they get reefed on, the can distort the carburetor body. This is not desirable.
Now you get to snug up the filter carrier and then the metal fuel line.

*** At one time there was a repair part for the carburetor filter carrier thread, but I have not seen one in decades and am not sure that they are
still even available. ***

This can't be all that hard, I have done it a bunch even before I had the coach.

Matt
--
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
 
> Dave,
>
> Please take to heart the cautions about the thread in the carburetor body. This is easily damaged and I have witness this more than a few times.

Thanks Matt. We really should compile these little instructions of yours.

Meanwhile, what is your gut call on the tanks?

Here's the story; when the coach was rehabbed in 2013 the tanks were probably removed and cleaned. At the very least, the bottoms were painted.

When i got the coach it had a lot of gas in the tank. I removed about 12 gallons but i was only able to add about 20.

In all likelihood it sat for those seven years mostly full.

Hopefully not too much rust formed.

What else can I do short dropping the tanks ?

--
Dave & Ellen Silva
Hertford, NC

74 Birchaven, 1-ton and other stuff
 
If I had the plans to cross country with the coach as
You do. And i had any fuel delivery questions. Drop the tanks and either replace all or check/verify all.

If you have the wood ramps. It really is a weekend job to replace all fuel lines.

You can see inside tanks and make a decision on those easily.

Fuel delivery problems are way too common. And very annoying as the coach seems to run fine until it doesnt’t.

would start by setting up an electric fuel pump to run through a fuel filter system and back
To the gas tank.

Cycle the gas through through a filter and can check flow.

A fuel pressure gauge is also nice to have.

--
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
 
Jon R:
You Sir are so practical and free w/ good advice - keep up the good work for all our GMC’ers!
Mike/the Corvair a holic

Sent from my iPhone

>
> If I had the plans to cross country with the coach as
> You do. And i had any fuel delivery questions. Drop the tanks and either replace all or check/verify all.
>
> If you have the wood ramps. It really is a weekend job to replace all fuel lines.
>
> You can see inside tanks and make a decision on those easily.
>
> Fuel delivery problems are way too common. And very annoying as the coach seems to run fine until it doesnt’t.
>
> would start by setting up an electric fuel pump to run through a fuel filter system and back
> To the gas tank.
>
> Cycle the gas through through a filter and can check flow.
>
> A fuel pressure gauge is also nice to have.
>
>
> --
> Jon Roche
> 75 palm beach
> EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
> St. Cloud, MN
> http://lqqkatjon.blogspot.com/
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
I wholeheartedly agree with Matt about how to go about changing the filter.

I brought my new coach 1000 miles back from Texas in July. It had water in the fuel, and several folks suggested changing the carb filter. I bought
one, but then the coach decided it would run mostly fine with enough Heet in it that I did not try to change it. When I got home, I polished (diesel
boat term) the fuel by draining it all and pumping it through a filter/water separator with an external electric pump. So then it was time to change
that filter. It had been stripped and JB Welded in. If I had tried to change it on the road, I'd have been screwed as it just fell out in pieces when
I put a wrench to it.

Chuck Boyd had a 78 parts coach and sold me another carb.

At least three companies I have found will drill and helicoil a stripped out carb body so it can be salvaged.

I bought one of the thread repair fittings Matt spoke of. Basically, it is just a standard filter housing with four slots milled in the threads so it
will recut the stripped threads in the body. In my case,

there were not enough threads remaining for it to work, so I plan on shipping it off and having it helicoiled by someone who has the tools and
expertise to do it right.

Take five minutes and pull the carb off the intake as suggested so that you can reinsert the filter assembly by hand and you won't strip the threads.
--
Greg Crawford
KM4ZCR
Knoxville, TN

"Ruby Sue"
1977 Royale
Rear Bath
403 Engine
American Eagle Wheels
Early Version Alex Sirum Quad bags
 
When checking the inside of the tanks besure to use a mirror and check the
inside top of the tank. That is where my rust was at as the bottom of the
tank looked clean. Jim Huppy was the guy that pointed it out to me.

On Mon, Dec 21, 2020 at 3:26 PM Greg Crawford via Gmclist <

> I wholeheartedly agree with Matt about how to go about changing the filter.
>
> I brought my new coach 1000 miles back from Texas in July. It had water
> in the fuel, and several folks suggested changing the carb filter. I bought
> one, but then the coach decided it would run mostly fine with enough Heet
> in it that I did not try to change it. When I got home, I polished (diesel
> boat term) the fuel by draining it all and pumping it through a
> filter/water separator with an external electric pump. So then it was time
> to change
> that filter. It had been stripped and JB Welded in. If I had tried to
> change it on the road, I'd have been screwed as it just fell out in pieces
> when
> I put a wrench to it.
>
> Chuck Boyd had a 78 parts coach and sold me another carb.
>
> At least three companies I have found will drill and helicoil a stripped
> out carb body so it can be salvaged.
>
> I bought one of the thread repair fittings Matt spoke of. Basically, it is
> just a standard filter housing with four slots milled in the threads so it
> will recut the stripped threads in the body. In my case,
>
> there were not enough threads remaining for it to work, so I plan on
> shipping it off and having it helicoiled by someone who has the tools and
> expertise to do it right.
>
> Take five minutes and pull the carb off the intake as suggested so that
> you can reinsert the filter assembly by hand and you won't strip the
> threads.
> --
> Greg Crawford
> KM4ZCR
> Knoxville, TN
>
> "Ruby Sue"
> 1977 Royale
> Rear Bath
> 403 Engine
> American Eagle Wheels
> Early Version Alex Sirum Quad bags
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class
 
> If I had the plans to cross country with the coach as
> You do. And i had any fuel delivery questions. Drop the tanks and either replace all or check/verify all.

Yeah, i'll probably end up doing that. Hope to get in on a lift in a couple weeks to swap the trans, at which time i will have someone more
knowledgeable look at everything and tell me what to do.

Then the plan is to daily drive it (better MPG than my Excursion) and put a few thousand miles on it over the next few months. That should shake the
cobwebs out pretty well.

And of course, if this dirty fuel problem does not go away I'll drop the tanks. But my hunch is if the tanks and fuel lines were refreshed in 2013
and it was left full, that may not be necessary.

--
Dave & Ellen Silva
Hertford, NC

74 Birchaven, 1-ton and other stuff
 
Just make sure your head is on the other side and not over it.\One can also
insulate for noise.
I prefer the Onan as most of repair shops that work on the GMC coach are
familiar with the Onan.

On Wed, Dec 23, 2020 at 6:13 AM dave silva via Gmclist <

> > If I had the plans to cross country with the coach as
> > You do. And i had any fuel delivery questions. Drop the tanks and
> either replace all or check/verify all.
>
>
> Yeah, i'll probably end up doing that. Hope to get in on a lift in a
> couple weeks to swap the trans, at which time i will have someone more
> knowledgeable look at everything and tell me what to do.
>
> Then the plan is to daily drive it (better MPG than my Excursion) and put
> a few thousand miles on it over the next few months. That should shake the
> cobwebs out pretty well.
>
> And of course, if this dirty fuel problem does not go away I'll drop the
> tanks. But my hunch is if the tanks and fuel lines were refreshed in 2013
> and it was left full, that may not be necessary.
>
>
> --
> Dave & Ellen Silva
> Hertford, NC
>
> 74 Birchaven, 1-ton and other stuff
>
>
>
> _______________________________________________
> 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.gmcrvparts.com
1-800-752-7502
 
To Matt’s detailed filter instructions I add one more “trick”. A drop of light oil at the flair to fuel line fiction point. This helps prevent
the fuel line from “ winding up” when snugging the flair nut and acting like a torsion bar. Otherwise if wound up it wants to loosen with
hot/cold/vibration cycles and give mysterious fuel odor. The single drops will quickly disappear with no visual leak cues. Also makes next service
easier.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
John,
There are lotof great tricks, Never heard or used it.
Thank you for sharing that with us.
Also on brake lines.

On Thu, Dec 24, 2020 at 7:29 AM John R. Lebetski via Gmclist <

> To Matt’s detailed filter instructions I add one more “trick”. A drop of
> light oil at the flair to fuel line fiction point. This helps prevent
> the fuel line from “ winding up” when snugging the flair nut and acting
> like a torsion bar. Otherwise if wound up it wants to loosen with
> hot/cold/vibration cycles and give mysterious fuel odor. The single drops
> will quickly disappear with no visual leak cues. Also makes next service
> easier.
> --
> 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 Kanomata
Applied/GMC, Newark,CA
jimk
http://www.gmcrvparts.com
1-800-752-7502
 
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