2008 Artic Cat 400 4x4 Auto - Carb Problems

[robert63]

my cat only has 100miles on it and is in mint cond. since i bought it new in 2009 it has had what i believe to b a carb problem. going down a steep hill makes it want to stall. as soon as u r on level ground its fine.and at top speed it kinda acts like its starving for gas. u let off the throtel a bit n its fine. idels good starts good. hav taken it back to dealer several times. they eithor said it didnt do it or mayb bad gas. my friend says it sounds like the float level isnt rite. any advise would realy help.

[oxidized_black]

swampcat07 will be the go to guy on this one. he answers EVERYTHING about arctic cat

if you want to send him a message in the meantime, he's here : swampcat07's ATV Page » QUADCRAZY ATV Community

[robert63]

i have a 2008 articcat 400 4x4 auto i bought new n 2009. it is in mint cond. only has 100 miles on it. my problem is when i go down a steap hill it trys to dye on me. as soon as i get on level ground its fine. and at full throtle it bogs down just a little. if i let up on the throtle just a bit its fine. starts great idles great. done this since it was new. had it back to dealer several times. they eithor said it didnt do it or acouple of times they said mayb bad gas.my friend told me it sounds like a float problem? any help or ideas would b great

[swampcat07]

Rob welcome to the forums.

I would start by draining the gas, cleaning the carb, and visually checking for air of vacuum leaks. I with today's gas I would not let it stand more than 2 weeks without an additive. Take the carb out and clean it either a jet could be obstructed, float sticking or the overflow on the bowl blocked. Check the intake boot and vacuum lines are secure. The down hill riding problem can be due to the engine breaking engaging and changing the idle of the engine.

I think cleaning the carb and new gas should solve the problem. Stop back and let us know how you are progressing.

I also merged both post so all of the replies can be in the same spot.

Edited April 30, 2012 by swampcat07
Merged Threads

[robert63]

thanks 4 repling. i hav drained fuel several times b4. and added octane boost per my dealer.the only thing i can think of is i had the quad 4 3days n it was leaking gas from the plastic tub on the carb. dealer said it was bad jet and replaced it?i have not taken carb off n cleaned it. but i will. i hav looked at hook ups n every thing looks new. thanks 4 the help Rob

[swampcat07]

I was guessing there may have been something obstructing the main jet. If the dealer worked on the carb and it is a carb problem I would take it back to them first. Sounds like the float was stuck and overflowing, did they say if they cleaned the carb when they replaced the jet? Only seems logical. Also they could have used the wrong size jet or put the carb back together wrong. (Slide, Clip, Diaphram, etc)

The other place I would check besides the carb is for an obstruction/problem in the air intake system. Mice Nest, Dirty Filter, Loose Connection, Open Airbox Lid.

[robert63]

thanks 4 your advise. the more i think about it. it nev had the slugish top end until after they said the replaced the jet thats akk they said. quad was only 3days old at the time they did that. they hav sinced closed down n its hard finding another dealer that will even talk to me since i didnt buy quad from them. go figure. il try some stuff u said n let u no. thanks again

[swampcat07]

I think you should have around a 136 keihin size on the main jet. If it is a diffrent brand let me know and I will see what size it should be.

Also you should do a plug chop and see if you are runing rich or lean. If you need help with that let me know.

[Bubbadodat]

Hello ,I thought I would share this problem with you all ,My 2008 AC 400 would start fine, it would idle fine , it had good midrange ,it had good high RPM's when it was not under torque

when I would want power it would start sputting like the choke was stuck , I did all the things I have done in my 68 years to fix such problems !! Carb clean, Carb rebuild , Filters ,checked coil , 

I was ready to give in and take it in ,I hate to give in , then I read one post about the diodes ,it was something I never would have checked!!!! In the fuse box I went ,I have been in there once for a fan fuse

I don't remember ever touching the diodes but evidently I DID . THEY ALL MUST BE GOING IN THE SAME DIRECTION ! It now will not stay on the ground ! UNBELIEVABLE. Hope it helps somebody.

 

[Mech]

Good bit of information there Bub, but I think it'll get lost in this thread.. Or maybe not, there are better searchers than me.

I had a look at the wiring diagrams and it looks like only the auto models have those three diodes in the fuse box. I'll have to have a better look one day and see what they do.

Well done on getting it sussed..