I have a 2004 Arctic Cat 400. It has been hard starting for awhile now that its cold out it has started some new problem. When I get it started it wil idle but as soon as you touch the throttle it dies and sometimes pops. It does this no matter how long I let it idle. I haven't touched it so starting from scratch on problem solving any ideas?

 

Here are just a few thing's that come to mind , Dirty Carb , Dirty air filter and or valve's need's adjustment , it could also be an air leak between the carb intake boot , carb to air filter boot , check to make sure there's no leak with the engine running after engine warm up and idling by spraying Deep Creep , WD40 or carb cleaner at these connection's ; if there's a leak at one of these connection's the engine RPM's will increase .

If this happen's it could as simple as tighting the the clamp's , or there could be a crack in one of the boot's ; i would suggest that you also check the air filter it's self for a dirty air filter clean and re oil air filter if it's dirty .

If it still stall when you throddle's up i would check the valve clearance for proper spec's , i know this may sound a little silly but i would also check your spark plug for proper gap ; and see if the plug is tight i've had people that i ride with me have the same problem and the fix was just the spark plug wasn't torqed (tighted) enough !

I have a 2006 Arctic Cat 400 FIS Auto 4x4 that was to start frome day one , if i didn't start it up and tke it for a ride every day i would run my battery down trying to start the engine ; my problem was a bad fuel hose the cheap hard plastic fuel and vent hose that the Factory install's is crap !

I replaced all these plastic hose to the Rubber GoodYear automotive type 1/4" hose and the automotive hose clamp's and my problem of hard starting was solved , i also had to replace the O.E.M. battery that came with my quad with a maintainance free ventless with more cold cranking amp's battery from Auto Zone ; i don't know about your year model but my 2006 AC 400 FIS Auto 4x4 has a clock that draw's juice from the battery even with ignition switch turned off and drain my O.E.M. battery down if it wasn't ridden at least once a week . I've gotten use to removing the battery cable's if i'm not going to ride my quad every day !

I hope this help's you out and one of these suggestion's is the fix for your AC 400 , and welcome to the forums !

williebee.........

 

Mine is similiar in problem.
Hard to start when cold, will idle rough and will stall many times until warm if I give it a little throttle.
I have been advised to check the gap and also the air filter may have too much oil and to clean it and apply less oil.
Will advise if either of these fix my issue....

 

What color is you spark plug after it idles a few minutes.

Light tan = good
dark and gooey = Bad

Hard starting can be from a lack of fuel, plugged fuel line, fuel shutoff valve plugged, gunk in carb blocking jets, valves out of adjustment, Air leaks, not getting enough air. So yhere are lots of things it could be.

However, you said that its new thing is to die and pop when you give it gas. The pop is usually from excess fuel in the combustion chamber. Is it popping out the exhaust? If so your air-fuel mix is off. Although a carb cleaning may help this I think you should look at the air filter and air-fuel mixture screw as well.

Get some Seafoam fuel additive and use it as well. It can keep these issues from happening by cleaning the fuel system but also acts as a fuelstabilizer if yiu do not ride very often.

Hope this helps.

Swampy

 

I haven't been on the site in years because of health concerns I just had hip surgery just 2 months ago so bare with . Have you ever had your valves ajusted , I had to adjust mine on my 2006 400 fis auto at 200 miles and I bought mine right off the show room floor on Feb 2nd 2006 ; not saying thats the case with your though you could have something as simple as a loose connection from a loose carb mount bolts or any of the clamps that hold your air intakes together but I hope this helps! Oh and about the valve adjusts the hardest part for me was having to remove the front clip now that was a buger ; have good one ! williebee......

 

Willie....the thread is 6 years old.