I have this 2000 artic-cat 300 2wd-4wd , that floods the engine cylinder with raw gas if it sets for a day or two. Go to start and the engine locks up, have to hold the decompression lever and crank it over acouple of times throwing the fuel into the exhaust. Dealer said to shut the fuel valve off, which I did , but that too also leak gas thur and still flooded engine, and dilutes the oil. which I am getting tired of changing. Recently replaced the float needle valve, and the tank shut off valve. Left the tank valve turned on position, and two days, engine cylinder full of gas again. Now shutting off the valve and that does keep cylinder from filling to the point it won't crank over. I still think whatever fuel is left in line going to carb is probably still seeping in to some point. The needle valve seat the dealer says is not available, made into carb body, it did look like it might be changeable. Look to be held in place by a small screw off to the side, and an o-ring seal around it. Has anyone else out there, had this problem. Dealer told me there was no recall or service bullitens on this. He said bad gas must have cause this. The machine only has 115 miles on it, and has had this problem for half of that. Any help would be appreciated.

 

beemer,
When you park your bike, leave the engine running while you shut off the gas. Let the engine run until it quits on its own, now the carb is bone dry of gas. (I do this every time when I am finished riding for the day) Now you have another problem you should change the oil because you have gas mixed in with it. use a synthetic oil. You might have damage your cylinder and piston rings with that raw gas. If it happens again, take out the spark plug and put some transmission oil in the cylinder. Click on THIS, it' s a diagram of your carb. I think there is a seat you can buy. If you are taking your carb. apart again, blow it out with compress air and put a gas fliter on. You can pick one up at a motorcycle shop.
I hope this helps.

 

Boy this can be aggravating. I know what you are up against. I havent had this problem with my Cats but have had it with 2 different BMW motorcycles. In both cases They had been setting a long time and had not been getting used much. New floats and needles did not fix them at first. I think what happens is that shellac (spel) forms on the inside of the tank,fule lines and carb bowls and it is hard to get it all out the first time or 2 you go into it. These carb are not as forgiving as automolbile carbs as every thing is so much smaller ant it takes very littel to scew them up. Lack of use seems to be very hard on them. Be patient and keep at it ,make sure the float is not binding up on its pivet pin.These small carbs are very finicky but once you get all the small crud out of the fuel system it will be fine . I have started useing fule stabalizer in some of my small engines and it seems to be helping. Any one eles tried this ? I wish I could tell you some magic voodoo to perform but persistents seems to work best. Good luck and let use know how it works out.[img]i/expressions/face-icon-small-smile.gif[/img]

 

great posts. i think if you let the carb run dry (like bigcat says) you will stop the problem but it wont fix it. i think you have carb problems but it is not bad gas. does it idle and run alright? something is sticking in you carb and it sounds like a needle.

 

On the subject of fuel filters, If there is enough room, try to put the filter in so that the gas has to run up hill to get to the element in the filter. This way it will also act as a sediment trap. If gas is allowed to run down hill to the element small dirt and rust particles can vibrate there way though the element.[img]i/expressions/face-icon-small-smile.gif[/img]

 

I had that happen on my 300 too, never had to change the needle & seat but did have to adjust the float height. At 115 miles I'd hardly think the Needle & seat is wore out?? When you pull the carb apart be sure to blow up the seat hole with compressed air to be sure there is no plastic fileings above the seat periodicly holding the needle open. Also adjust the float height to the low position, that'll put more pressure on the needle & allow the bike to run better in off camber positions which my bike did have a problem doing. Good luck

 

Both times I have had the carb off and apart, I have blown compress air up the the needle valve seat , in case there was any crap in the passage, and I did add a small motorcycle type inline filter in the line before the carb. Also I bent the float tab just a slight bit more so it would put alittle extra pressure on the valve. As suggested, running the engine dry on fuel to prevent flooding problem, I have done a few times, but it takes awhile to use that fuel. So here you sit waiting , so you can shut the key off. I am going to try and run this alot more than I have in the past hoping it may clear up. I have mainly used the cat for working purposes on the property, so that is why the milage is so low. Other than this carb problem, I have been very happy with the performance and power of the machine. Thanks to all that have responded.

 

I just thought of something else. This is kind of like looking for a needel in a hay stack, but one more thing you will want to watch for is when you push your fuel line on to the barbed fittings on the carb,fuel shut off,and filter be careful that the barb is not so sharp that it cuts a small pice from the in side of the fuel line witch would then be in the system with out you knowing it. Im just trying to think of anything that may help you.

 

Just another thought? With the poor quality fuels these days & the low mileage you have it's possible your needle & seat are varnished enough to not let them seat? Did you try a new needle & seat?

 

I did install a new needle, but the seat the needle goes into, the parts guy at the dealer said that was part of the carb body. It did look changable to me, but when ordering the float needle valve from Cat, all you get is the needle. So after putting that in, I thought my problem may have been taken care of. So I let the cat sit for 2 days with gas valve on. Went to start it, and engine rolled maybe a half a revolution and lock. Cylinder full of gas again. For now I am turning off the fuel and I have changed the oil again.
Thanks for your help.
Beemer