Wonderwoman

Man these Arctic Cats run no mater what is wrong with them. Found out the Pilot screw had vibrated out of the carb. In other words running with no Pilot screw. Have one ordered should be here Friday. This old machine won't know how to act. Glad that it has just been little things. Will let you know how it runs with a pilot screw.

Alright, the head is back on and it is running. Have a slight problem with idle and it wants to backfire if you have it reved up and let off the throttle. I am thinking these are all carb issues. Reset the valve clearance twice now since reinstalling the head. So looks like time to look at the carb to get the final issues worked out.

Ok, the head is in the shop. Got a new intake valve and two new valve oil seals. Machinist says everything else looks great. Will have it done in a week. Can't wait, hubby will be so happy to have his machine back and running again. As long as I am at it my 250 is acting the same so after we get the red one back together I am going to pull the head off my 250 and get it done right away. For less than $200 each to get these back up and running right it is well worth it. Maybe another 10 years will go by then with no issues. Still love the Arctic Cats even with the valve issue.

The piston is low enough in the jug that I felt the cylinder wall. Smooth as a baby's behind. I would almost bet the machine on a valve issue. So for now it will be the valve job professionally done and see what happens. As much as I have read about these Arctic Cats and the valve issues I am hoping this takes care of it. Will let you know when I get the head back and put back together. Thanks for all the help.

Redid compression and could get it up to 80 psi if you dump a little oil down the spark plug hole. Ok took the top end off this weekend. Found out the intake valve was almost loose. Could compress the springs with my thumbs to get the valve free and out of the head. Looks like the valve face has worn and is sitting low in the head. Any advice here since I have never done valve work on any small engine. If this is the issue then I will take it to a professional to have it redone. While I am this far I think I will put new rings on the piston as well. Piston looks great.

Valves are adjusted to spec. .005 intake, .010 exhaust. Will try the new spark plug and recheck the compression tomorrow and do have it in neutral. Is the timing adjustable on these? I thought I read in the manual that it is factory set and no adjustment.

Thanks, hubby did the compression test. I will redo this weekend and see what it says.

With that low of PSI would that keep it from starting though?

I am hoping that someone here can give me some more ideas. Our poor old red 300 won't start. We rode it, running fine, shut it off and now it won't start. Have gas to the carb and spark at the plug. Valves are adjusted. Still won't start. Tried a little starting fluid in the air chamber and still won't start. This poor old machine has 7000 miles on it. That has to be an Arctic Cat record! And I have never touched the engine besides setting the valves. Unfortunatly it looks like it only has 60 psi of compression. Don't understand how it could be running fine and then nothing. Someone give me a clue as to what I am missing or what to check. I was going to rebuild the top end this next spring but didn't want to do that this winter in a non-heated garage. Any help?

Hey my arcitc cats are notorius for needing the valves adjusted at least once a year. Hard starting and backfire going down hill is my warning signal. The specs for mine are on a stick on spec sheet on the rear of the machine. It isn't hard to do and only take a couple of min.

Hey you may want to check the air filter too. If it is plugged with dust I have experienced the same symptoms.

Hi, just a suggestion but try setting the valves. I have a 2000 ac 300 and a 2003 ac 250 and once they got a few hundred miles on them I had to start adjusting the valves for hard start and backfiring.

Yep, did everything correct for installing a seal. I haven't had a chance to look at the repair manual yet but I am still leaning towards a pressure problem.

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Me and my Arctic Cat 250 "Might Mouse" sometimes have to pick a different route than the big boys so I don't get high centered. We still have fun.

I have a 2003 Arctic Cat 500 Green automatic. I have just put in the third seal in the front where the drive line goes into the rear end. Put it together spun the tires, while it was up on the stand and no leakage. Took it out for 1/2 mile test ride and I'll be dammed if it wasn't leaking again when I got back. First time I replaced the seal I didn't use OEM. So I ordered two seals from Arctic Cat and Hubby replaced the second one. He isn't as mechanical as I am so thought he messed up. I spent 3 hours on replacing it this time. Made sure all parts were cleaned and fit good. Now it is leaking again. Am I missing something here? Is there a vent for the rear end that may be plugged and causing excess pressure to make the gear grease run out around the inside of the seal? I am open for suggestions.

Well thanks to everyone for their help. I put in a new needle and seat and the problem went away.

Hey, been there, done that. You need to adjust the valves. We have a 2000 red 300 Arctic Cat and I have to adjust the valves every year. I have a 2003 green 250 and have never touched the valves. Go figure. But the 300 has 6000 miles on it now.

If you don't have a good service manual spend the $70 and get one, it can be a lifesaver.

Get the valves adjusted before doing any adjustments on the carb. Good luck

Thanks, will try a new needle and seat and check the float level and boyancy this weekend.

Nope not flooding on start up. It was actually spewing gas out that hose that goes from the air box all the way up by the gas tank and then comes back to just below the air box while riding. I replaced the spring in the diaphram part of the carb, made sure the carb was cleaned good and all settings were per the service manual. We have 6000 miles on this machine and it has never been a problem up until now. If the float height is messed up would that allow gas to back flow into the air chamber????

Well this started as gas going out the air box side of the carb all the way around in that hose and dumping gas all over the machine. I took the carb apart, cleaned it well and put it back together. I then adjusted the valves to make sure everything was kosher. When I took the cap off the bottom valve I was greated by 1/2 pint of gas with a little oil in it. So after adjusting valves and putting everything back together I changed the oil. Started it up and rode it for about a half an hour. No more gas spewing out of the air box hose. Let it sit overnight and went to start it. Wouldn't start, lifted the compression release and it started. Smelled like gas coming out of the exhaust again. What should I check? What is letting gas get into the cylinder?