Looking for some help troubleshooting an electrical/heat issue with a 2003 400i 4x4 auto machine. Starts/runs great for about 20-25 min. and then you would think it has a rev. limiter keeping it from coming off of idle. Will cough, spit, backfire, etc. but will not move. Let it sit 1/2 hour to an hour, then I can run it for another 20-25 minutes before it starts all over. Looking at the coil since it is right over the engine and maybe the heat is getting to it. Tried cleaning the connections going to the coil. Thinking about buying a new one, but would prefer to know it is bad before spending 80 bucks on a new one.

Anybody have any ideas on this?

 

There have been a number of people who have had their gas tank vent hose plug up or get pinched.
Sounds like that might be the problem.
When it starts to act up, loosen the gas cap to see if there is a vacuum in the tank.

The vent hose should terminate under the instrument pod. Try blowing air in it to make sure it's clear

 

Well, that is one thing that I have not looked at (and probably wouldn't have looked at). What is the theory behind it? Is it causing some sort of vapor lock when it heats up?

At least this will be easy to test when it starts messing up. Calling for snow on Christmas so hopefully I will have to clear the driveway with it then and I will let you know if the gas cap makes any difference.

Thanks for giving me something to try.

Merry Christmas!!!

 

These hoses can eventually plug up with dirt, mud and crap. They vent the gas tank so as the fuel is used up it doesn't start pulling a vacuum in the tank starving the ATV of gas. The symptoms you describe look kind of like that. Eventually the air does get to the tank when oit sits for a while which is why (if that's your issue) it will run well for a while and then start running badly again. I had an old Valiant once that had that exact issue. The previous owner had replaced the gas cap with a locking one that wasn't vented.
I've seen quite a few people in forum threads that have had the same issue with Arctic Cats. To keep my vent clear I made sure the hose was high in the instrument pod and I inserted a piece of tubing bent downward so water would drain out if splashed up in there. No issues so far. If you leave the gas cap tight until the problem starts again, shut the ATV off and listen cosely as you slowly open the gas cap. If you hear air hissing you will know that you found your problem.
I am guessing your vent tube is under the instrument pod but I have never seen a 2003 vent tube . Sometimes the hose will fall down and really get plugged up.

Merry Christmas to you and youir family and good luck finding the problem.

 

Well, it doesn't appear to be the vent tube. When it happened the first time today. I slowly opened the gas cap and didn't hear anything. I also disconnected the vent tube to see if that would help...and it didn't.
I figure this has to be electrical, but I just am not sure how to test for it. what voltages should be where, etc....
The only thing I had done that I was worried about was putting a dynojet kit on it a few years back so I reversed all of that today. Put the original needle and jet back in. I then took some heat reflective tape and put around the coil. the bike seemed to run a little longer, but then it decided to quit again. I left it out in the driveway to cool off and I will go move it into the building here in a few.

Man, this is getting frustrating!!!

 

Yeah, I've been there before.

If you don't have a repair manual you can download one at the following site for free. There is also a file for wiring diagrams which may help. Just select the file and right click on it and save to your computer.

Electrical trouble shooting is in chapter 5 and fuel in chapter 4.
"K&T Parts House Lawn Mower Parts and Chain Saw & Trimmer Parts"

One last thought re the fuel system, make sure your carb vent hose is not kinked or plugged

Keep us posted to what you find. I'm not sure what would cause those symptoms that would be electrical.

You might also post over at
ATV's - ArcticChat.com - Arctic Cat Forum

There is a wealth of AC info over there.

 

Thanks for the link. I will do some reading tonight. I got to thinking today that it might be fuel related since it always runs about 20-30 min regardless of outside temps and I had both side covers off today.
It actually started idling rough today before quitting and then it wouldn't restart right away. I loosened the screw on the bottom of the carb and some gas did come out the hose so it wasn't completely empty, but it would not start. Went back 45 minutes later and it started right up.
Wondering if the gas may not be flowing fast enough...

 

It does make sense that it's being starved for fuel.

You must have adequate fuel flow for it to run 25 minutes but something is causing the flow to be restricted after that time. It all points to a blockage due to floating crud in the tank or a blocked vent.

Did you check the vent tube on the carb? This hose is vented to the atmosphere so it is attached to the carb at one end and is open at the other.

There should be three rubber hoses attached to the carb,

1) The small diameter one for the float bowl drain on the bottom of the carb.

2) The fuel hose which attaches to the carb on the left side (when you are sitting on the ATV)

3) The vent hose which attaches to the right side of the carb which is the vent hose. If this one is restricted it could cause an issue. This vent hose will likely end up the same place your gas tank vent hose ends but I am not sure.

 

And the saga continues.....
Disconnected the tube from the tank and the upper tube from the carb. Ran for about 30 minutes and then it shut down. Took the gas cap off, tried reserve on the fuel petcock and nothing is helping.

Starting to look less fuel related and more electrical now. Feel like I am chasing my tail.

 

I personally never rule out a fuel problem unless I remove the carb and clean it. I have chunks of goo pop in and out of places that they are not wanted in the float bowl. They are usually either green chunks or a brownish algae like substance that my friend tells me is being formed from an additive the EPA has the manufacturers put into the fuel to make it burn cleaner.

In the past a friends machine acted similar and we originally suspected the CDI or Coil. However, when his machine stopped running in my shop as we were trying to fix it. WE were able to remove the spark plug, then leaving it attached to the plug wire and grounding it out we turned the engine over to try to start it. After I peeled my friend off the ceiling and he had changed his pants (yes, he was touching the plug when hit hit the start button) we had ruled out an electrical issue. He assured me that there was PLENTY of #%&$_**** spark. We then looked at the carb/fuel and found our problem. He also had an air filter that was particularly nasty. We cleaned the carb and air filter and his problem was cured.

So I would clean the carb to make sure you can rule out a fuel problem as well as make sure your air filter is clean (or remove it to see if it effects it).

Then check the plug. The plug color can give you some info too: White - too hot usually not enough fuel or lean, Tan (or a Tanish white)- Perfect temp, Black-too much fuel (or too rich). If you attempt to check the spark after it dies I would suggest you either have a friend hold the plug or make sure it is grounded good and watch for the spark. Should be blue spark and usually you can hear it (especially if your friend is holding it)

Hope this helps
Swampy