Fuel from carb overflow

[BillBee]

Arctic Cat 400 - recently fuel started pouring from the carburetor bowl drain. The drain screw was tight. I've removed the carburetor and cleaned the bowl, but with the drain screw secured fuel continues to pour from the overflow. The float appears to be operating normal.
What would cause the fuel to poor from the overflow?

 

[SpudHauler]

Remove carb, remove bowl, remove float, remove inlet needle and blow out the line from the hose on the carb through to the inlet needle. You have dirt stuck under the inlet needle.

 

[TOMMYHPX4X4]

i second the dirt in the carb. what i do is get some carb cleaner and use the little red tube that comes with it abd shoot in into all the holes after the needls are removed that is. and sometimes it's not dirt but a tar like gunk that forms on the needles and walls of the needle bodies.it might take you a few cleanings to get it all out but thats what i would do.

 

[BillBee]

Thanks I'll give what you suggest a try. But it appears to be more of a seal problem, when I take the bowl off and fill with a small amount of fuel, the fuel leaks out the bowl drain with the bowl drain screw in place.

 

[SpudHauler]

Ok, that makes sense. The drain has a bad seal or the bowl has gotten corroded over the years and the drain screw is not seating properly. Try a little silicone around the screw and then put it back in and let sit over night to harden before putting the bowl back on. Might be a cheap fix.

 

[BillBee]

Ok, that makes sense. The drain has a bad seal or the bowl has gotten corroded over the years and the drain screw is not seating properly. Try a little silicone around the screw and then put it back in and let sit over night to harden before putting the bowl back on. Might be a cheap fix.

Thats a good idea. Silicone will withstand fuel don't you think? Thanks.

 

[TOMMYHPX4X4]

silicone and gas don't mix .the gas will eat it up fast and then you'll get bits of silicone stuck in the needle valves.i would stick to just cleaning it out .i know one thing thats real good to use in the cleaning but your wife might get mad at you .take her eyelash brush and clean the eye lash stuff off that will give you a verey small bore brush it work pretty good.i think they even sell them small brushes in the gun cleaning section to but they are kinda hard to find so it might be worth the fussing from the wife for a few minutes to get the parts cleaned.then take her to the store and let her buy a new one she'll get over it and you'll have a new little tool for your tool box.you could buy a gun cleaning kit with those little brass barrel scrubbing brushes but most have the metal protruding through the end so you might have to look at a few of them to find one withut the metal coming through the end.something good to use also is breakfree powder blast gun cleaner but just make sure you let it dry really good and wash it after because it's kinda rough on some rubber and plastics but it does a really good job of breaking down gunk and blowing it out.

 

[TOMMYHPX4X4]

plus one other thing i forgot to mention is if it's the jet needles that are sticking sealing up the bowl will keep the gas in it but it will also just flood the engine too . you have to find what jet valve is doing the leaking and fix it. i tried the silicone thing on lots of leaking gas tanks only to have the fuel eat the silicone and break it down .

 

[SpudHauler]

Good point Tommy, about the gas and silicone not mixing.

But if you put it on the threads and o-ring area it should not really see much gas and will be just behind the hole it is meant to plug. Worth a try.

Hard to tell what he is looking at from thousands of miles away eh! :laughing:

We love pictures :thumbsup:

Good luck!

 

[TOMMYHPX4X4]

your right about that pictures help out alot.

 

[grsthegreat]

I had the same issue with my manual push snowblower. i must have forgotten to put the ethanol eliminator sta-ble in the previous year. the gaskets in the carb were toast. that ethanol ate right thru them. leaked like a sieve that winter. Im sure glad the Govt has eliminated ethanol subsidties...maybe that garbage will stop being put into the fuels

 

[BillBee]

Sorry I don't have a pic, the ATV is at the weekend place, but let me try to provide more detail.
The carburetor bowl started leaking without every touching the drain screw. I removed the carb and cleaned the bowl with the drain screw in place and I could blow through drain. When I removed the drain screw there's no difference when I blow through. I cleaned the drain with light air and reinstalled the drain screw, but it will not seal as I am able to continue to blow through it. When examining, I don't see any o-ring and the maintenance parts manual does not indicate it has one, and that is the reason why I'm puzzled by the leak. It's as if there's deterioration in the bowl's drain preventing the screw from sealing.

So I think some type of sealant around the drain screw would resolve the matter, I was thinking perhaps that gas tank repair sealant.

I checked the cost of a new carb it's $385.00 and I prefer not to do the purchase until all other options are exhausted.

Thanks.

 

[TOMMYHPX4X4]

i'm 100 %sure there should be an o ring on that drain screw thats what seals it up. try going down to napa or an auto parts store and see if you can get one .they should have them .i have an o ring kit with about 30 diferent size o rings and 50 of each one i bought it at napa years ago and i am still not even close to useing it up.it was money well spent .i replaced the o rings on many carbs with it .but like i said that screw should have an o ring on it.

 

[SpudHauler]

Maybe you are mistaken on what your a cleaning. The drain is off the bottom of the bowl right. With screw out and bowl filled with gas, it flows out. With screw in and bowl filled does it still flow.
Now if it doesn't flow out in the above situation but does when it's back on the ATV, you are back to what I said originally, your float is stuck open, usually dirt under the inlet needle.
You see there is a higher drain inside the bowl that lets excess gas flow out the overflow in these situations. It's secondary to your bowl drain and only overflows in situations when the float is stuck open by dirt, usually.

 

[BillBee]

i'm 100 %sure there should be an o ring on that drain screw thats what seals it up. try going down to napa or an auto parts store and see if you can get one .they should have them .i have an o ring kit with about 30 diferent size o rings and 50 of each one i bought it at napa years ago and i am still not even close to useing it up.it was money well spent .i replaced the o rings on many carbs with it .but like i said that screw should have an o ring on it.

Okay I'll check but the manufactures manaul does not indicate there is an o ring.

 

[BillBee]

Maybe you are mistaken on what your a cleaning. The drain is off the bottom of the bowl right. With screw out and bowl filled with gas, it flows out. With screw in and bowl filled does it still flow.
Now if it doesn't flow out in the above situation but does when it's back on the ATV, you are back to what I said originally, your float is stuck open, usually dirt under the inlet needle.
You see there is a higher drain inside the bowl that lets excess gas flow out the overflow in these situations. It's secondary to your bowl drain and only overflows in situations when the float is stuck open by dirt, usually.

Yes, the drain is off the very bottom of the bowl and it leaks with the screw tightly in place and I can also blow through it with the screw in place just as if the screw was removed. When I blow through it I can feel the air excaping from the inside of the bowl at the drain, not the higher drain inside the bowl that lets excess gas flow out.

The f

 

[SpudHauler]

Well BillBee that is a tough one.
You may have to take the bowl and screw down to your local shop and see what they say.
You definitely found the problem. But what caused it is now the mystery.
Keep digging.

 

[TOMMYHPX4X4]

unless i missed it what year is your cat maybe with more than one person searching the problem we can help you out more.

 

[TOMMYHPX4X4]

i done a little reading on some cat forums and it seems there is a o-ring and they do mention to watch very closely that it doesn't fall out they do mention that sometimes it gets stuck inside the houseing and turns sideways and then causes a leak .you might wanna check that out but i would like the year model so i can do a better search for you.

 

[tcreeley]

I had a motorcycle with a rusty tank. My carb would overflow, I'd clean it and it would overflow again. Bits of rust would get under the inlet needle and keep it open. An inline fuel filter stopped the problem.
On my farmall cub I got a tube of gasket maker and used that to seal my warped float bowl to the carb. It also helped around my drain screw. It came in a gray and a gold color depending on the temp. No silicon and gas resistant. I used it on the intake manifold of my motorcycle for a positive seal when I was juryrigging a new carb connection. Let it dry a day or two before you use it. Holds up well.
Air is great for carb cleaning. If you don't have a compressor, tape some fuel line on the end of a bicycle pump hose and pump air through that way.