Fuel Filters

[Carl Stouffer]

I have been fighting fuel starvation issues for years, so I try to keep up with maintenance to help my fuel system be the best it can be. Today I
replaced the two in line filters under the coach and the carb inlet filter on the Q-jet.

After replacing the filters, I cut one of the in-line filters and the car inlet filter open to have a look at the elements. Both of the in-line
filters appeared to be free flowing and no dirt came out of them when I blew them out into a rag. The carb filter had the slightest amount of very
fine grit in the pleats, but it didn't seem excessively dirty.

I don't remember when I last replaced these filters, but I'm sure the carb filter, at least was replaced less than 8000 miles ago.

How often do you guys replace fuel filters and what do you use as a criteria for when to replace them. They are cheap, but not quick and easy to
replace, making me reluctant to waste any more time on them than absolutely necessary.
--
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

 

[jim kanomata1]

It is not the particullates that is restricting the flow but the gum that
the ethanol is washing off ALL sides and top of the tank.
Just replace them all and go for another 10,000 miles.
It will get better and will not have problems later.
Be sure to run down the aux tank also as there are lot of gum there as that
tank selcom gets used up.

> I have been fighting fuel starvation issues for years, so I try to keep up
> with maintenance to help my fuel system be the best it can be. Today I
> replaced the two in line filters under the coach and the carb inlet filter
> on the Q-jet.
>
> After replacing the filters, I cut one of the in-line filters and the car
> inlet filter open to have a look at the elements. Both of the in-line
> filters appeared to be free flowing and no dirt came out of them when I
> blew them out into a rag. The carb filter had the slightest amount of very
> fine grit in the pleats, but it didn't seem excessively dirty.
>
> I don't remember when I last replaced these filters, but I'm sure the carb
> filter, at least was replaced less than 8000 miles ago.
>
> How often do you guys replace fuel filters and what do you use as a
> criteria for when to replace them. They are cheap, but not quick and easy
> to
> replace, making me reluctant to waste any more time on them than
> absolutely necessary.
> --
> 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:
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>

--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502

 

[thomas phipps]

Replace them as part of your spring 'cleaning', getting the GMC ready for the season's travel. Easier at home, than along the side of the road.
Tom
--
2012 Phoenix Cruiser model 2552
KA4CSG

 

[Ken B]

Back in 1996 (I believe it was) we in the Chicago-Milwaukee EPA non-attainment area were forced to go to E-10 year round and it has been that way here
ever since. MTBE was not approved or supplied here.

In 1995 and 1996 there was lots of doom and gloom articles with lots of added hype like Y2K about how we were all going to have fuel filter, fuel
line, injector, fuel pump, and carb problems. There were opportunists trying to sell their preemptive fixes for big bucks. Not many people bought
into it and did anything to prepare. They just used whatever came out of the pump and went on their way.

Since E-10 and 100% gas (E-0) came out of the same refinery and same terminals and were mixed at time of loading the delivery truck, the EPA placed
their enforcement arm on the delivery truck drivers. It was a flat fine of $25,000 for any fuel truck driver caught dropping E-0 at a retail gas
station in a non-attainment county. Off vehicle pumps road like farming, boats, and aviation, etc. were exempt.

Well nothing happened after in or after 1996 and in the 20+ years since then everybody has forgotten about the projected problem. I hate ethanol
diluted gasoline as much as anyone for other reasons but the forecast disaster just never happened.

Around here where you think it might have been needed most, it is impossible to find any place stocking ethanol rated fuel line / hose. It can be
special ordered for 3 times the normal line/hose prices.

I needed 3 feet of 1/2" fuel line a couple of months ago for a gas vent line on a GMC. I special ordered 3 feet from Oreily and the computer took the
order. They had the standard 1/2" hose in stock, as did AutoZone, and Advance. In order to fill the 3 ft. order the warehouse sent a 100 foot roll
and it took 3 days to get there from who knows where. They sold me 3 feet and put the rest in stock expecting to never be able to sell it. Their
computer said that they had never sold that item before. They also did not stock ethanol rated hose in 1/4, 5/16, and 3/8 sizes.

The place ethanol did cause a problem was when pilots used it in airplanes, which is illegal. It softened up some of the sealants used in wet wing
tanks causing them to seep. When the fuel in the tanks was replaced with non-ethanol diluted 100% gasoline the seeping stopped.

We all know that ethanol makes a good detergent. So if you are now using E-10 and your fuel system if full of junk (primarily varnish) from years of
neglect, I suspect that over a period of time E-10 will dissolve that stuff and it will get carried away. If it is a rust issue you have it can also
get carried away but not dissolve. If there are large particles greater than 10 or 20 micron they should be caught in the carb and inline filters.
Hose problems, and fuel pump problems from E-10 I have never seen.

I have seen some very old hoses get very hard but they would have gotten that way over 40 years E-10 or not. I have one very hard one going to my
Onan that someday I'll replace.

So based on over 20 years of local experience with mandated E-10, I do buy into to all of the E-10 hype.

There are still many other reasons not to like E-10 and I still use 100% gasoline whenever possible in my airplane, GMC, small engines, and cars.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

 

[Carl Stouffer]

I redid my fuel system in 2010 with all ethanol resistant hose from Applied GMC. At that time, my tanks were spotless and have never had anything in
them except E-10, with the exception of a few tanks of E-0 which it ran much better on.

I run through probably about 600 - 700 gallons of gas per year, so I doubt that there is any kind of build-up in my tanks. The only thing I found in
the cut open filters was a very minor amount of grit, mostly in the carb filter.

I use Wix filters and understand that the 3/8" in line filters (33033) do not filter as fine particles as the carb filter (33048) so I understand some
dirt getting past them. I'm guessing the fuel filters have little to do with the fuel starvation problems that I just can't seem to get a handle on.

Of all of the recommended remedies for this problem, the only ones I have not yet done are in tank fuel pumps, and fuel injection. The frustrating
part is that the problem comes and goes and seems to have more to do with the gas - source, winter/summer mix, etc. than anything else.

We head up to Las Vegas on Friday for a trip to visit my daughter, son in law, and two grandchildren, so we'll see how it goes this time.

--
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

 

[Russell]

Carl,
The Qjet fuel filter is inexpensive and easy to replace. I put a new one in at every oil change (

 

[Ken B]

Changed mine 10 or 12 years ago. I have one inline from each tank and one in carb. The socks are still on in the tanks (I think). If they ever get
dirty I'll change them then. It is an easy job. I do carry spares somewhere in the coach. I have a Blazer with 240,000 miles on it. I have never
changed that filter. Laurie's Jimmy had a gas gauge sending unit go out last year at around 150K miles. Heather changed that filter at the same
time that she replaced the fuel pump sending unit for Laurie. You could still blow through the removed one.

I do not think that they need to be changed very often.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

 

[Ken H.]

Me neither, Ken. I don't think I've EVER changed one on Anything.

Ken Filter-Lucky H.

> ​...
>
> I do not think that they need to be changed very often.
> --
>

 

[jim kanomata1]

One thing we are seeing;
One need to use the fuel from the Aux tank and use it down to at least 1/4
mark to keep the tanks half way clean.
Keep in mind that the filters will accumilate more particulets and gum from
the aux tank so prepare to change the fuel filters.

On Mon, Jan 8, 2018 at 6:53 AM, Ken Henderson
wrote:

> Me neither, Ken. I don't think I've EVER changed one on Anything.
>
> Ken Filter-Lucky H.
>

>
> > ​...
> >
> > I do not think that they need to be changed very often.
> > --
> >
> _______________________________________________
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--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502

 

[Matt Colie]

From a lifelong history of managing fuel inventory, we use a standard method that has served us very well (now that everything works).
* Run on the main tank until it indicates half.
* Change to the Auxiliary (that will start at about half) and run it until the low fuel light comes on.
* Change back to the main and run it until the next planned fuel stop.

Part of this idea is to try to keep above the 1/4 on the main so there is fuel for the APU (genset) in case it is needed.
Another part of this thinking is that as the main fills first when fueling, we can count on getting new fuel in both tanks.

How many of you have been riding a motorcycle and reached down to change to the reserve only to find out that you left the fuel cock in the reserve
position after you last filled the tank?? (I am not going to ask for a show of hands....)

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

 

[Jim Hupy]

I kinda do what Matt does with the following exceptions. I ALWAYS fill my
tanks in the cool morning, and I fill until I hear gasoline gurgling back
in the filler neck. I always use major brand (Chevron) gasoline from busy
fuel stops. When under way, I run on the main tank exclusively. The late
coaches use from both tanks down to the point where the filler spigot no
longer allows fuel transfer between level tanks. In my case that will be
225 to 250 miles. That will equal 4 hours of seat time, which in my
opinion, requires one to get out and take a break from driving. I usually
do this at a fuel stop unless I have reached my destination. I add fuel
enough to reach my destination with sufficient fuel available to run the
generator if I am dry camping, although the Royale coaches that were
upfitted by Coachman do not use the extra fitting in the main tank with the
siphon tube that ends at 3/4 of the tank depth. That allows for morning
fill ups as part of my morning maintenence checks. Just what I do, drive on
the top half of the tanks.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

From a lifelong history of managing fuel inventory, we use a standard
method that has served us very well (now that everything works).
* Run on the main tank until it indicates half.
* Change to the Auxiliary (that will start at about half) and run it until
the low fuel light comes on.
* Change back to the main and run it until the next planned fuel stop.

Part of this idea is to try to keep above the 1/4 on the main so there is
fuel for the APU (genset) in case it is needed.
Another part of this thinking is that as the main fills first when fueling,
we can count on getting new fuel in both tanks.

How many of you have been riding a motorcycle and reached down to change to
the reserve only to find out that you left the fuel cock in the reserve
position after you last filled the tank?? (I am not going to ask for a
show of hands....)

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

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[Ken H.]

Jim K. has a point in suggesting frequent use of Aux fuel. I always use
the Main, unless it starves the engine, then I switch to Aux and go to the
next service station. However, as my tanks are plumbed, there's always
flow through the Aux unless I'm using from it: The return from my EFI
accumulator tank feeds into the bottom drain on the Aux tank, keeping it
full and overflowing to the Main.

Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI & EBL,
Manny Brakes & 1-Ton, Troy-Bilt APU, etc., etc., etc.
www.gmcwipersetc.com

 

[Ken B]

I quite frequently (not always) run on the aux tank feed just to exercise the selector valve. When I see the level dropping on the aux and not on the
main I assume that I have run that tank and the main below the 7 gallon point and I know the valve and fuel system is working as designed.

When I rad people never run below 1/2 tank I question why fill it up and carry all of that extra fuel around? If you are only going to run to the 1/2
point then only fill them 1/2 (plus a little) in the first place. I fill them and run until the low fuel light comes on unless I find a cheap or
non-ethanol station before then. I have no idea how far the coach will go after the light turns on because I have never run it to the point of
running out of fuel.

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

 

[Jim Hupy]

Last time I checked, I cannot push or pull a GMC Motor home by hand.
In hot weather, I do occasionally experience vapor lock. I have an
auxiliary fuel pump connected to the auxiliary fuel tank valve so that when
I change the position of the switch from main to auxiliary, the fuel pump
will run. I NEVER, EVER, run any vehicle I own below 1/4 of a tank, and
gages on a GMC are notoriously inaccurate. You are free to do anything you
wish in this regard. I wish you well.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

> I quite frequently (not always) run on the aux tank feed just to exercise
> the selector valve. When I see the level dropping on the aux and not on the
> main I assume that I have run that tank and the main below the 7 gallon
> point and I know the valve and fuel system is working as designed.
>
> When I rad people never run below 1/2 tank I question why fill it up and
> carry all of that extra fuel around? If you are only going to run to the
> 1/2
> point then only fill them 1/2 (plus a little) in the first place. I fill
> them and run until the low fuel light comes on unless I find a cheap or
> non-ethanol station before then. I have no idea how far the coach will go
> after the light turns on because I have never run it to the point of
> running out of fuel.
>
>
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
>
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[Ken B]

I also have never tried to push a GMC. I did have to tow mine home once with my Blazer after it quit a mile and a half down the road. I had changed
the selector valve and the new one had a crack in it. That is when I learned about needing vacuum to stop. It taught me why I needed an electric
vacuum boost pump.

I do remember Arch once pushing his GMC with his towed vehicle. It was only a short distance.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

 

[jim kanomata1]

Also keep in mind that the tank selector switch has a rubber O ring, it is
being eaten by the ethanol if it has not been changed in the last 4-5 years.
As i metioned before, the percent of ethanal is never at 10% and it is a
real killer when it goes higher in concentration.
When the Wix ( now a Mann) rep comes over to see me, I will be questioning
him about what he has seen out in the field.

> I also have never tried to push a GMC. I did have to tow mine home once
> with my Blazer after it quit a mile and a half down the road. I had changed
> the selector valve and the new one had a crack in it. That is when I
> learned about needing vacuum to stop. It taught me why I needed an electric
> vacuum boost pump.
>
> I do remember Arch once pushing his GMC with his towed vehicle. It was
> only a short distance.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
>
> _______________________________________________
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--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502

 

[richard h staples]

I've followed this discussion with some interest, esp those who report finding rust/dirt in their systems, and also the comments about water and
alcohol. Thought I'd throw in my .02.
A. Water in the fuel is rare, but once you've got it, it's nasty. We got a tankful of bad gas once, on our first cross-country trip ~20 yrs ago.
Filled up at a small-town gas station in Pa, and the dance was on. Drygas, filter change, helped a little, but it was several thousand miles before
the hiccups faded away. Moral: Buy gas from a large, busy, station when possible.

B. In my former life as a mechanic/service manager in Massachusetts 25 yrs ago, I often dealt with waster/ice in fuel systems, so I did some
research about it. Seems alcohol-laced gas is even MORE susceptible to water than plain gas. As I understand it, alcohol has a MUCH greater affinity
for water than it does for gasoline. In fact, oil companies add things to get the alcohol and gas to stay mixed. If you get much more than a few
ounces of water in your tank, the alcohol will part company from the gasoline, join up with the water, and sit at the bottom of the tank. You CAN run
a car on pure alcohol (They do it in Brazil.), but it won't vaporize in cold weather, and it takes TWICE as much fuel per volume of air, so it won't
burn in a normal vehicle.

C. Many places I've worked changed fuel filters at every major (annual, biannual) service, even though NOT recommended by the manufacturer. This
was done to insure that no money was left untapped in the customer's wallet, IMHO. I recall the Nissan manual that simply said "If the fuel filter
becomes clogged, change it." I have seldom if ever found a clogged fuel filter, unless the the tank was rusted badly, or run without a gas cap. The
one time I thought I had a clogged fuel filter, it turned out to be a rusted-out fuel line sucking air.

D. About 15 years ago, I dropped the tanks of "The Dancing Bear", and replaced most of the hoses and O'rings. Last year (2016), fuel was spilling
over when filled full, so I dropped them AGAIN, replaced ALL the hose with SAE70R9 and/or steel, and pulled both pickups to replace O'rings. I found
(to my surprise) totally clean tanks and totally clean fuel socks. I found one pickup sat rather high off the bottom of the tank, so I bent it down a
little. Finding NO debris in the glass bowl filter of my electric pump's prefilter, I removed it as an unnecessary flow restriction. It's amazing how
many different sizes of hose are needed for all the fuel lines, vent lines, fill vent lines, fill pipes, generator fuel line, ad nauseum. This job
took longer than last time, now that I'm on the wrong side 70, so I hope it's the last time. Afterwards, the tanks even built up a little pressure as
they should. Vapor lock is greatly reduced (but not totally eliminated).

HTH
--
Rick Staples, '75 Eleganza, Johnstown, CO

"Advice is a dangerous gift, even from the Wise to the Wise, and all paths may run ill." -Tolkien

 

[Ken B]

Water in fuel is common in these coaches because people park them for extended periods of time (primarily in winter) without the tanks being full.
When they are warm, humid air enters the empty space in the tanks. Then as the temperature changes to cold, the humid air inside the tanks condenses
moisture on the inside and eventually settles as a liquid on the bottom. If there is ethanol diluted fuel in the tank, then the ethanol will combine
with the water on the bottom to make the total amount accumulated there even more.

We use water as a standard check for ethanol on our gasoline at the airport. We put 1 CC of water in an measuring tube and add 5 cc of the suspect
gasoline. If it is E-10 the test tube will read 1.5 cc on the bottom of combined water and ethanol and 4.5 cc of gasoline above it. I use a medicine
bottle graduated in ounces but the result is the same. In EPA non-attainment areas, the EPA is very strict and the test always comes out at exactly
10%. The EPA allows a 1% variation (9% to 11%). Anything over or under that and the delivery truck driver is subject to a huge fine. In other
attainment areas the amount will vary any from 0 to 10 %. I have never seen a reading above 10% except on these ethanol pumps with E-85. With E-15
on the horizon that might change.

Enough of that, this subject is suppose to be about filters and water in tanks.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

 

[jim kanomata1]

Richard,
Your comments are well expressed, however, one need to know that this is a
45 year old object that has been exposed to sitting around and OLD fuel
does crutalize to som extent and the gum that also develops.
Gas stations have similer problems.
My experince along with many other owners have this residude issue.
If your addressing only the particulet issue, your going to be in for Pearl
Harbor attack.
ALso using the Aux tank and utilizing it is a wise idea.
Oh, Newer cars do not need to address it as they are not 45 years old and
driven frequently.

> Water in fuel is common in these coaches because people park them for
> extended periods of time (primarily in winter) without the tanks being full.
> When they are warm, humid air enters the empty space in the tanks. Then
> as the temperature changes to cold, the humid air inside the tanks condenses
> moisture on the inside and eventually settles as a liquid on the bottom.
> If there is ethanol diluted fuel in the tank, then the ethanol will combine
> with the water on the bottom to make the total amount accumulated there
> even more.
>
> We use water as a standard check for ethanol on our gasoline at the
> airport. We put 1 CC of water in an measuring tube and add 5 cc of the
> suspect
> gasoline. If it is E-10 the test tube will read 1.5 cc on the bottom of
> combined water and ethanol and 4.5 cc of gasoline above it. I use a
> medicine
> bottle graduated in ounces but the result is the same. In EPA
> non-attainment areas, the EPA is very strict and the test always comes out
> at exactly
> 10%. The EPA allows a 1% variation (9% to 11%). Anything over or under
> that and the delivery truck driver is subject to a huge fine. In other
> attainment areas the amount will vary any from 0 to 10 %. I have never
> seen a reading above 10% except on these ethanol pumps with E-85. With E-15
> on the horizon that might change.
>
> Enough of that, this subject is suppose to be about filters and water in
> tanks.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
>
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> Unsubscribe or Change List Options:
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--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502

 

[john r. lebetski]

Seems tanks are either opperating room clean or nasty. If clean, you don't need add-on filters (added fail or fire risk) and if the tanks are nasty
due to dirt in filter evidence, they need to be dropped and corrected.
--
John Lebetski
Woodstock, IL
77 Eleganza II