Gas leaking

dahermit · Jul 21, 2020

1948 8N, front mount.
I went out to mow with my 8N today. I took my "gas gauge" stick and inserted it into the gas tank...shocked to find no gas on stick at all...it should have been 1/2 full. Looked into the sediment bulb and it looked like there was gas in it. I figured I must have misjudged the amount of gas I had left in the tank. So, I opened the sediment bulb valve hoping it would start and have enough gas to get me to the outbuilding where I store my gas.

It started right up, but soon faltered and quit. I figured that I had run out of gas, so I carried a can of gas from the gas shed and poured it into the tank thinking it should start right up.

However, no go...acted like it was flooded. Upon examination, I found that gas was dripping from the carb, but I did not find
that the nut on the gas line was loose, nor the bottom bottom drain bolt seemed loose.

I took a screw driver and loosened the collar on the air inlet hose and gas poured out.

I have concluded that the valve on the sediment bulb must not be sealing (I always turn it all the way in when done with the tractor...without fail, not wanting gas to leak into the carb if the float were to stick.

I have also concluded that along with the sediment bulb valve must not be sealing, the float in the carb must be allowing gas to flood the carb and run out the air intake hose joint.

I can replace the valve stem in the sediment bulb, but am not sure what to do with the sticking float...or even for sure that is the problem.

Any insights on my problem? I am too old and decrepit to do much on the tractor, nor really interested in getting too involved due to my medical condition (I will need it for plowing snow this winter though), but I think I am up to at least changing out the sediment bulb valve...or should the whole thing be replaced?

Bruce (VA) · Jul 21, 2020

Did the gas go on the ground or in your
oil pan?
75 Tips

Bruce (VA) · Jul 21, 2020

Just replace the sediment bowl assembly.
Order a new needle and seat as well. Easy
to replace.
75 Tips

carlntexas · Jul 21, 2020

(quoted from post at 18:33:33 07/21/20) 1948 8N, front mount.
I went out to mow with my 8N today. I took my "gas gauge" stick and inserted it into the gas tank...shocked to find no gas on stick at all...it should have been 1/2 full. Looked into the sediment bulb and it looked like there was gas in it. I figured I must have misjudged the amount of gas I had left in the tank. So, I opened the sediment bulb valve hoping it would start and have enough gas to get me to the outbuilding where I store my gas.

It started right up, but soon faltered and quit. I figured that I had run out of gas, so I carried a can of gas from the gas shed and poured it into the tank thinking it should start right up.

However, no go...acted like it was flooded. Upon examination, I found that gas was dripping from the carb, but I did not find
that the nut on the gas line was loose, nor the bottom bottom drain bolt seemed loose.

I took a screw driver and loosened the collar on the air inlet hose and gas poured out.

I have concluded that the valve on the sediment bulb must not be sealing (I always turn it all the way in when done with the tractor...without fail, not wanting gas to leak into the carb if the float were to stick.

I have also concluded that along with the sediment bulb valve must not be sealing, the float in the carb must be allowing gas to flood the carb and run out the air intake hose joint.

I can replace the valve stem in the sediment bulb, but am not sure what to do with the sticking float...or even for sure that is the problem.

Any insights on my problem? I am too old and decrepit to do much on the tractor, nor really interested in getting too involved due to my medical condition (I will need it for plowing snow this winter though), but I think I am up to at least changing out the sediment bulb valve...or should the whole thing be replaced?

heck your oil you may find your gas in oil pan.

dahermit · Jul 21, 2020

Thanks for the heads up, I will check the oil but inasmuch as I see a big stain in the oil absorb granules under the carb, I think it has been dripping on the floor. But it seems to be a good idea to check anyway.

whereswaldo · Jul 22, 2020

Bruce, is it even possible for an updraft carburetor to be so tightly sealed that a drip, drip of gasoline could reach the intake manifold?

Tim PloughNman Daley RIP · Jul 22, 2020

Leaking gas is mainly from a bad fuel valve - a $6 part, APN-9194. There is a seal on the internal stem that wears out. Also, fuel and brake lines use a special thread - 7/16-24 UNS, and many times fellas booger up the inlet port on the Bulb and/or the Fuel Inlet Brass Elbow with wrong threads. Rubber hose to air inlet port leaking indicates possible stuck float. You don't need a whole new Sediment Bulb. The Valve Stem is the only working wear part.

The main causes of fuel leaks are #1, #2, and #3 sediment bulb valve stem. The valve stem is the only working part in the system and it will wear out the seal on it and leak. It is OEM Ford part number APN-9194 and costs $6-$8 at reputable dealers like nnalert. If you pay anymore than that then they are ripping you off. #6 failure is from worn, cross threaded, or wrong fuel line fittings at sediment bulb inlet and/or at brass elbow carb inlet. Use the correct OEM-type fuel line, made exact and pre bent too. Using plastic, copper, nylon, or rubber is NOT recommended. Leak #4 comes when fellas leave the fuel valve knob on when they shut down the tractor. If seal is getting bad, it will leak if left ON and/or when opened. Leak #5 can be caused by backed up vacuum in stem if gas tank vent is plugged, and leak #7 can be caused for same reason if brass fuel line inlet at carb is plugged at the filter.

#1. OEM FORD APN-9194 SEDIMENT BULB & VALVE STEM VIEW DIAGRAM:

#2. APN-9194 SEDIMENT BULB VALVE STEM FUEL:

OEM SEDIMENT BULB ASSEMBLY & VALVE STEM:
#3.

#4. OPEN VALVE STEM 2 FULL TURNS FOR MAIN OPEN POSITION, FULL FOR RESERVE POSITION, OFF POSTION WHEN NOT IN USE:

#5. GAS TANK VENT PLUGGED, MAY CAUSE NO-FLOW CONDITION:

FORD TRACTOR FUEL SEDIMENT BULB FILTERS:

Tim Daley(MI)

dahermit · Jul 22, 2020

Shouldn't the carb be taken apart, needle valve seat replaced, float checked to see why it has not been shutting the gas off?

Bruce (VA) · Jul 22, 2020

" Bruce, is it even possible for an updraft carburetor to be so tightly sealed that a drip, drip of gasoline could reach the intake manifold?"

Yep.

It sure is. See tip # 9.

Here is a good illustration of what can happen:

" We just had an 8N in the shop that the owner wanted us to fix the carb leak and replace the starter because the engine wouldn"t turn over. Turns out the base had more gas in it than oil and the bearings didn"t get enough lube from the diluted oil and seized the engine. I think of that tractor every time I park my tractors now and don"t forget to shut the fuel off. "

(YT Post 10/10/07)
75 Tips

dahermit · Jul 24, 2020

Addendum: I have ordered a new sediment bulb assembly. I also want to put a rebuild kit in the carb. I took the carb off and am in the process of cleaning it up.

I noticed that some kits have a new drain plug. Mine is buggered-up...stuck, will not turn with a box-end wrench. Any suggestions (only from people who have been successful, in getting a buggered one out)on how to get it out? I have no faith in penetrating oils.

HFJ · Jul 24, 2020

vise grips

dahermit · Jul 24, 2020

I have tried vice grips and have had to apply way too much torque than I am comfortable with...still would not move. At his point, I have taken the carb apart and had considered using a propane torch to apply heat. But then, my schooling in Cast Iron makes me think that I could end up heat cracking the carb, so no heat.
I have ordered a rebuild kit that seems not to have a new drain plug so I am inclined just to leave that stuck plug alone. Besides, in the years I have owned the tractor I have never used that drain plug...always disconnected the fuel line instead.

Gas leaking

dahermit

Member

Bruce (VA)

Well-known Member

Bruce (VA)

Well-known Member

carlntexas

Member

dahermit

Member

whereswaldo

Member

Tim PloughNman Daley RIP

Well-known Member

dahermit

Member

Bruce (VA)

Well-known Member

dahermit

Member

HFJ

Well-known Member

dahermit

Member

Similar threads