fuel leak around manifold

labjack

Member
Tractor is a 63 4000 gasser. I visit "Ol Blue" once every week or two. Last few times I tried to start her it would turn over but not start and gas would spray/seep out somewhere around the manifold area. It will eventually start and run kind of rough for a bit and then seems to run fine after that. There's no visible gas leak before starting and oil doesn't seem to have gas in it. On a possible related note(or not) after about 45 minutes it starts running rough, especially under load. Haven't tried troubleshooting that issue yet. On that subject(troubleshooting) I know there's been a lot of good info on here, much of it in bits and pieces. Does anyone know of a link to a good comprehensive step by step process for troubleshooting spark and fuel issues? Thanks for any help, Mark.
 
It's hard to tell, but I was assuming it was leaking from around the intake manifold. Can't be sure though.
 
leaking where carb bolts to manifold? or where manifold bolts to head? Intake or exhaust manifold?

Is carb flooding and fillling manifold full of gas?

Or.. are you seeing oil or something drip downwards?

If manifold leaks gas, its leaking bad enough... to make it almost impossible to run... Thats why we all dont know how to answer your question.

If it runs somewhat ok, the manifold cant be leaking very bad... If it idles well, manifold has to have a very very good seal. In some cases a dead cyl can spit gas out the exhaust pipe but it ususally burns up in the exhaust due to high heat...
 
Well, I can't see exactly where it's coming from. It only happens when trying to start it after setting for extended periods(1-2wks) in my case. I thinks it's coming from exhaust manifold but can't be sure. It's a little rough running at first but eventually starts running good even at idle. As I stated in op after about 45-60mins. it starts running rough again,not sure if that is related to the startup issue or not. When I say leaking I mean as it's cranking gas starts spitting out from one of the areas you mention. Once it starts and stays running the leaking pretty much stops best I can tell. That's about the best I can describe it.
 
labjack- Just a wild guess...


1. Does it have a vertical exhaust tube?

2. Does the tractor sit out in the open or in a covered garage/shed?

3. If it sits outside, do you have a 'rain cap' on top of exhaust tube? Or put a soda can over the exhaust tube?
 
No, under shed and horizontal exhaust. It's definitely gas that is spraying out. Could it be a carb(float) issue?
 

If you want help with this YOU need to be the eyes and ears and nose. You need to do better than "area". Once you can ID exactly where the gas is "spraying" out, you will probably get a firm explanation of what is happening and how to fix it.
 

Have you checked your engine oil dipstick? If the level is high and thin, your carb needle and seat is leaking gasoline through until it fills the manifold and runs into the cylinders.

Are you shutting the fuel off under the tank when not in use?
 
I haven't been shutting the tank off but I don't think there's gas in the oil. It's actually down a little on the dipstick and it doesn't smell gassy. Everything appears to be dry externally around the carb area until cranking it over.
 
Ok, I'll be going down this weekend and I'll see if I can get a better handle on what's actually going on. Maybe I should start a new thread after that since this one's fading into oblivion.
 
(quoted from post at 23:10:38 03/09/16) Ok, I'll be going down this weekend and I'll see if I can get a better handle on what's actually going on. Maybe I should start a new thread after that since this one's fading into oblivion.

Or if you use modern view it bumps up.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top