Gas draining out of inline fuel filter

1945 - 196*, Willys CJ series, questions, discussions, regarding anything related to the post war jeep.®
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Bob Bell
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Gas draining out of inline fuel filter

Post by Bob Bell » Thu Dec 21, 2017 12:45 pm

The last few days I have had to crank the motor for a while to start the jeep in the morning. No fuel in the carb. Lifted the hood this morning, and as i suspected there was no fuel in the inline filter I have between the pump and the carb. So the gas is dripping back into the pump. What i can't figure out however is why there is no gas in the carb reservoir either? Where is that going? Can it be draining down through the carb into the intake manifold.

My sense of smell is not that great, and I have sniffed the dipstick long and hard, but can't really identify if I CAN smell gas or not. I am assuming the disappearing gas would be drawing through a pinhole in the diaphragm in the pump down into the sump. There are no telltale marks / stains under the vehicle that would suggest gas dripping onto the floor.

Complete disclosure: I changed out the carb over a week ago. No starting problems for four or five days, and now this. Coincidence?
So gas is disappearing from filter AND the carb. Are these two problems related? I don't see how the gas can possibly siphon itself out of the carb and back into the fuel line.

As I worked on this today, I do see that the rubber lines that the filter is attached to need replacing, and I will do that immediately, and I'll replace the filter too as it due to be replaced.But I can't see that the problem really lies with the filter or the lines - by replacing them I feel I am pre-empting future problems.

While I was working on the vehicle this morning, I had the line with filter unhooked. When I started, the filter was half full of fuel. An hour later it was a quarter full. As I was checking it every few minuted, I was able to see that there was no visible sign of fuel leaking out of the rubber hose, or through any fittings.

Yesterday I experienced fuel problems on my way home - jeep wouldn't idle at the lights- had to heel and toe to keep it running. I discovered this morning that the square pipe plug that screws into the idle port had fallen out. That has been replaced, and currently the vehicle idles nicely. This little factoid would not appear to have any bearing whatsoever in the 'disappearing gasoline' syndrome.
I'm sure others have experienced similar problems - I had a quick search through the forums but have not, so far, found a similar post.

Bob
Last edited by Bob Bell on Thu Dec 21, 2017 3:53 pm, edited 1 time in total.
Bob Bell

1946 CJ2A 36116
Have owned dozens of flat fenders over the years including 1945 CJ2A 10011 which I sold in 2002.
First 4WD was an Austin Champ in 1965, and then a GPW UK license number HRO 443, sold in 1974.


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Re: Gas draining out of inline fuel filter

Post by artificer » Thu Dec 21, 2017 3:19 pm

Check your oil level is not rising or smelling of gas/petrol....once flow is started the line between these 2 components [when/if fuel in the carb bowl lowers/evaporates a bit CA ethanol? the needle valve opens] atmospheric pressure is now on the fuel in the line causing it to perform just as a siphon does draining the line to the lowest point.
John GIBBINS Member Institute of Automotive Mechanical Engineers [Ret], ASE Master Medium/Heavy Truck & Auto Technician USA -2002 Licensed Motor Mech NSW MVIC 49593 Current 2015
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.

Bob Bell
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Re: Gas draining out of inline fuel filter

Post by Bob Bell » Thu Dec 21, 2017 3:52 pm

My oil level is not rising visibly - I mean there are not pints just pouring in. It is hard to read the dipstick in thousands of an inch. If you read my post, you will have noted my statement that my sense of smell is poor and that I could not definitely say that gas is present.
I am just assuming it is - the gas HAS to be going somewhere.

The question is is it going back to the tank or to the sump? And why is the reservoir in the carb also empty by morning? No traces of gas on the outside of the carb. Could it be dumping into the intake manifold?

I have a vacuum / fuel type pump. I see online that I can buy an overhaul kit for $63 incl shipping https://www.ebay.com/i/202025511160?chn=ps or a complete new set up for $80 including shipping: https://www.ebay.com/itm/Jeep-Willys-CJ ... .l4275.c10

I already have two duff vacuum / fuel pumps, and I hate to add to the pile, but the $80 deal seems like a good 'un IF my problem is a leaky diaphragm.

Anyone have experience of these two items?

Bob
Bob Bell

1946 CJ2A 36116
Have owned dozens of flat fenders over the years including 1945 CJ2A 10011 which I sold in 2002.
First 4WD was an Austin Champ in 1965, and then a GPW UK license number HRO 443, sold in 1974.

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Re: Gas draining out of inline fuel filter

Post by artificer » Thu Dec 21, 2017 4:09 pm

No.
Don't do anything like that until you have properly isolated the problem.
Test the fuel pump first, make sure it is holding a vacuum & creating pressure. HF vacuum gauge for about $15 can save one heaps of unnecessary time lost & $$$ spending.

Fuel pumps are very trouble free & rarely need servicing, unless it got a gut load of crap or has been left full of corrosive water.

It is always best & less dangerous having a inline filter before the fuel pump & not on the pressure line to the carburettor.

One can download TM 9 1828A Fuel Pumps from www.jeepdraw.com, I believe.
John GIBBINS Member Institute of Automotive Mechanical Engineers [Ret], ASE Master Medium/Heavy Truck & Auto Technician USA -2002 Licensed Motor Mech NSW MVIC 49593 Current 2015
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.

Bob Bell
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Posts: 204
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Re: Gas draining out of inline fuel filter

Post by Bob Bell » Thu Dec 21, 2017 4:50 pm

I do have a manual vacuum pump, but I am not sure how to use it to test a Fuel pump. I looked on YouTube, where I DO often find great info, but everything there dealt with electric pumps and fuel injection. No info on where/how to operate a hand held manual pump.
Guess questions are:
1. What should pressure be?
2. To where do I attach / insert / push against with the end of the tube attached to the pump?
3. Does the engine have to be running / cranking? Hard to do that with a line detached!
Thanks,
Bob
Bob Bell

1946 CJ2A 36116
Have owned dozens of flat fenders over the years including 1945 CJ2A 10011 which I sold in 2002.
First 4WD was an Austin Champ in 1965, and then a GPW UK license number HRO 443, sold in 1974.

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Re: Gas draining out of inline fuel filter

Post by Scoutpilot » Fri Dec 22, 2017 1:43 am

Before you jump off into the deep end let’s establish a few facts, shall we?
1. 1946 CJ2A?
2. L-134 motor?
3. Carter or Solex carb?
4. If Carter, which model?
5. Exactly which fuel pump is attached? A photo would help.
6. What is the condition of the interior of the fuel Tank?
7. The fuel lines?
8. What size fuel line?
9. Steel, copper or rubber? If a mix, what is where?
10. How much gas in the tank?
11. How old is the gas in the tank?
12. Have you looked into the intake manifold and observed a puddle of liquid gasoline?
13. What is the condition of the heat riser valve?

We’ll start with these questions and move on with the facts established.
'70-'71 'A' Batt., 377th FA, 101AB
(Slicks and LOH's)(Col's LOH Pilot)
'71-72 CHARLIE TROOP,
16TH AIR CAV, 1ST AVN BDE (AEROSCOUTS)
LOW LEVEL HELL.
'46 CJ2A
'47 CJ2A
'48 CJ2A
'48 B1PW126
'69 CJ5

Bob Bell
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Re: Gas draining out of inline fuel filter

Post by Bob Bell » Fri Dec 22, 2017 10:14 am

Scoutpilot asked the following:

1. 1946 CJ2A?
2. L-134 motor?
3. Carter or Solex carb?
4. If Carter, which model?
5. Exactly which fuel pump is attached? A photo would help.
6. What is the condition of the interior of the fuel Tank?
7. The fuel lines?
8. What size fuel line?
9. Steel, copper or rubber? If a mix, what is where?
10. How much gas in the tank?
11. How old is the gas in the tank?
12. Have you looked into the intake manifold and observed a puddle of liquid gasoline?
13. What is the condition of the heat riser valve?

Here are the answers:

1. 1946 CJ2A
2. L-134
3. Carter
4. W-O
5. There is nothing on the fuel pump other than 'Made In Canada'. It has been on the jeep for about 8 years. For what it is worth, it replaced one that lasted less than a week that was identical.
IMG_3074.jpg
IMG_3074.jpg (114.36 KiB) Viewed 1785 times
6. Very good - tank was new in 2002. Flushed out within last six months.
7. New 1/4" OD steel fuel line from tank to new flexible short hose to pump. Put in at same time tank was flushed. 1/4" OD steel lines to carb from pump, with 7/16" OD rubber tube in the middle linking the plastic inline fuel filter. I plan to move the filter to the line between the tank and the pump, and install a new steel line from the pump to the carb. Presently the rubber tubing does need replacing - it could well be that there are very tiny air holes, although there is NO fuel seepage visible, and there is NO fuel starvation while driving the jeep, as is often evidenced when the carb sucks air rather than fuel!
8. See previous.
9. See previous previous
10. Currently it is full - it gets filled approximately once a week.
11. About two days
12. Yes I have looked, and no, there is no gas visible.
13. It operates as it is supposed to.

I checked out the vehicle this morning before writing this. The filter was almost empty, BUT the reservoir in the carb still had fuel, just above the metering rod jet.
I would think that it would have started quite easily this morning given the amount of gas in the reservoir, but as i wanted to look into the intake manifold, which entails removing the carb, I didn't want to fill up the filter, and thus deal with gas all over the place when I had to remove the carb, which would, of course, entail removing the line from the pump to the carb.

I do have replacement check valves in stock, but no replacement diaphragm. I do have two old pumps, but given the amount of work involved in stripping down an old pump to use what could well be a very dubious diaphragm versus buying a brand new one, I would rather go that route - IE getting a new one.

However, I don't want to buy anything until I know where the problem is.

I am interested in knowing how to use the vacuum pump.

Thanks for all your interest and suggestions,

Bob
Bob Bell

1946 CJ2A 36116
Have owned dozens of flat fenders over the years including 1945 CJ2A 10011 which I sold in 2002.
First 4WD was an Austin Champ in 1965, and then a GPW UK license number HRO 443, sold in 1974.

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Scoutpilot
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Re: Gas draining out of inline fuel filter

Post by Scoutpilot » Fri Dec 22, 2017 10:32 am

A couple more questions. Was this fuel pump purchased as New Old Stock? Used? Are you using Ethanol Gas or Non-ethanol gas?

Typically, a fuel line is the same size from tank to carb. Is the 7/16” rubber clamped to 1/4” steel?
'70-'71 'A' Batt., 377th FA, 101AB
(Slicks and LOH's)(Col's LOH Pilot)
'71-72 CHARLIE TROOP,
16TH AIR CAV, 1ST AVN BDE (AEROSCOUTS)
LOW LEVEL HELL.
'46 CJ2A
'47 CJ2A
'48 CJ2A
'48 B1PW126
'69 CJ5

Bob Bell
G-Command Sergeant Major
G-Command Sergeant Major
Posts: 204
Joined: Tue Oct 21, 2003 5:01 pm
Location: Oakland, CA

Re: Gas draining out of inline fuel filter

Post by Bob Bell » Fri Dec 22, 2017 11:42 am

The fuel pump was brand new, bought from Archer Brothers of Hayward, CA. Ron bought them out 7 or 8 years ago. The first one he sold me went bad immediately, and the one I am using now was its replacement.
I live in California, so I am sure most, if not all the fuel I buy has ethanol in it.
The fuel line, from tank to carb, has the same internal diameter, rubber or steel.
I just had a neighbor give me his opinion regarding the smell of gas in the engine oil. For what it is worth, he couldn't smell gas in it.

Bob
Bob Bell

1946 CJ2A 36116
Have owned dozens of flat fenders over the years including 1945 CJ2A 10011 which I sold in 2002.
First 4WD was an Austin Champ in 1965, and then a GPW UK license number HRO 443, sold in 1974.

Bob Bell
G-Command Sergeant Major
G-Command Sergeant Major
Posts: 204
Joined: Tue Oct 21, 2003 5:01 pm
Location: Oakland, CA

Re: Gas draining out of inline fuel filter

Post by Bob Bell » Fri Dec 22, 2017 12:01 pm

Thanks Luc, for the oil pressure info.
Oddly enough, I was just looking at the oil pressure. I had replaced the carb after this mornings inspection of the intake manifold, and just adjusted it to run at 650rpm, and was quite surprised to see the oil pressure at 30-35 psi! Of course I had only driven it up the road and back so although the temp was at 180F the engine had not really gotten really hot. I'm sure it will be back to normal after running for more than ten minutes.
Usually the jeep idles at around 20 psi at 650 rpm.

Bob
Bob Bell

1946 CJ2A 36116
Have owned dozens of flat fenders over the years including 1945 CJ2A 10011 which I sold in 2002.
First 4WD was an Austin Champ in 1965, and then a GPW UK license number HRO 443, sold in 1974.


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