8N fuel line leak

dhammel

Member
Greetings - I've just purchased an overhauled 2N with an 8N engine. Everything runs and looks great with one small exception. There is a fuel leak on the intake line connector at the bowl. The previous owner pointed this out and mentioned that he couldn't get it to stop so he always just shut the gas off after operating. I'm about to take it apart and check for any obvious issue like a bent flange or cross threading - but I'm wondering if this is common and if I should just replace that fuel line to make the fix easier. Gas leaking in any amount whatsoever just can't be a good thing!
 

I would expect thread damage in the bowl rather than the steel fitting. I had one like that. A previous owner had cross threaded the fitting. I eplace the sediment bowl and it is working fine.
 
How about teflon tape on the threads - or am I off to short cuts already.

Also, what fuel do you use in a 8N - can I use regular non leaded ?

Thanks much for your help!
 
Regular fuel is OK, but non-ethanol is better if you can get it. I would always turn the fuel valve off when you're done for the day. For your leak, you might get it to stop with tape, but you could get shards in the line that would cause worse problems later. Turn the valve to off, take off the fitting and get a replacement; if you're lucky it will be the one not on the line. If you're not lucky, the line has to be cut and a new fitting installed and reflared, and often there is not extra line so a new one is needed. They are not expensive..., 1/4" steel brake line at a good parts store.
 
just to clarify - you're talking about the glass sediment bowl assembly, right?

u can try teflon tape, but u need to understand that teflon tape is NOT a sealant. its only purpose is to lube the threads to make it easier for whatever you're working with to be tightened fully. if someone has crossthreaded the fitting into the sediment bowl, you're going to need to replace something, almost certainly - the sediment bowl assembly, the fuel line itself, or both.

and as jim has pointed out, u should always shut the valve on the sediment bowl off every time you're done using the tractor. this is a gravity fuel delivery system. if, for any reason, the carb float is sticking or otherwise not working properly, all of the gas in the tank can drain out thru the carb. and if your air breather intake happens to be clamped down firmly at the carb, that gas can end up somewhere bad. turning that knob to the off position as a matter of routine can save u a lot of grief if your float misbehaves.
 
New tractor? You will need the manuals. See tip # 39.

" How about teflon tape on the threads " No, it's a flare fitting. It doesn't seal on the threads; it seals on the flare.

"Also, what fuel do you use in a 8N - can I use regular non leaded ?"

See tip # 5.

Re the leak at the bowl.......

It's a steel fitting on a soft metal bowl. Which do you think will fail first?

Remove the bowl & check the threads. If you need a new bowl, make sure you get an oem style replacement from this site or nnalert's.
Also, what fuel do you use in a 8N can I use regular non leaded ?
 
(quoted from post at 12:45:07 04/03/17) just to clarify - you're talking about the glass sediment bowl assembly, right?

u can try teflon tape, but u need to understand that teflon tape is NOT a sealant. its only purpose is to lube the threads to make it easier for whatever you're working with to be tightened fully.

I beg to differ. PTFE tape is used to BOTH lubricate and seal threads and there are millions of examples of that all around us. Technically it is not a sealant but it fills the root gap on common NPT taper pipe threads which is where leakage takes place. The thread flanks seal themselves mechanically and unless damaged from prior assembly or improper forming need no sealant. PTFE tape of the proper density is even an approved sealant for NPT threads on fuel gas (natural, propane, butane, etc.) lines.

NPTF (aka Dryseal) pipe threads do not have a root gap and are mechanically self sealing on both flanks and root - e.g. no sealant required unless the threads are damaged or improperly formed.

TOH
 
(quoted from post at 16:16:03 04/03/17)
i stand corrected - kinda ;)

would u expect it to fix this particular problem?

No because the threads are not the seal. And in general I don't expect thread sealant of any kind to "fix leaks" - that usually requires replacing or repairing the damaged fittings or threads.

TOH
 
Upon close inspection it looks like the sediment bowl is the problem. I can see a deformed shape where the flange of the tube should seat. New sediment bowl is the fix.
 
Any type of fuel leak is an accident waiting to happen. Fix it ASAP. First, we need to know what you mean by 'fuel leak on the intake line connector at the bowl'. The way I read that makes it sound like the sediment bowl assembly is leaking at the top where it screws into the gas tank. That to me is the 'intake' side of the unit. Now, to add to the advice already given, you need to determine the root cause of exactly where the leak originates. IF the fuel line that exits the sediment bowl enroute to the carb inlet, is leaking there, you either have cross threaded the compression fitting female inlet port or it is the wrong one. The sediment bowl assemblies are made of pewter metal -relatively soft. The correct OEM fuel line is steel as are the compressions fittings on each end. You can buy the correct pre-bent lines at most Ford Tractor suppliers. Next leak issue with these is usually the valve stem. There is a rubber seal inside the stem that is to create a seal when the knob is fully closed. That seal will leak over time once it gets chewed up from opening and closing the valve. You can rectify simply by purchasing just the valve stem for less than $10 rather than the whole sediment bowl assembly -about $20 - if that is the cause of leaking. Always start those line fittings with your fingers and never force or apply a wrench til you have screwed it in as far as you can-you need to know what the 'feel' is. Ditto goes for the carb inlet elbow and oil lines. On the fuel sediment bowl assembly valve stem is attached the knurled knob by an 8-32 screw Often the screw will loosen up on its own and fall off when the tractor is running and thus so does the knob. I learned a long time ago to apply a dab of Loctite thread sealant on that screw when installing new valve stems to prevent that.

Sediment Bowl Valve Stem Assembly:
SEDVAL03.jpg

Worn Valve Stem Seals -Root Cause Of Many Fuel Leaks At The Bowl:
SEDVAL02.jpg
 

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