Spitting and sputtering 08 Sportsman 400

[justinmiller930]

Over the last few days I have been having a problem with my 2008 Sportsman 400 H.O. Here is a little background on what has been going on with it.

When riding around the yard, it spits and sputters during operation with the throttle pushed in. Most of this occurs during acceleration. It kind of chugs and acts like it doesn't want to run. When leaving off of the throttle, the machine will run, but when I let off completely, it wants to die. If I don't push the throttle in, it shuts off completely.

Starting the machine has been off and on. Sometimes it works fine and sometimes it is very difficult to start. The fuel switch is on and the tank has fuel in it.

I am not very sure what is going on with this thing. A week ago it was running fine. After driving around the yard, I parked it in the garage until I got it back out again. Any help and insight into this problem would be helpful. I am thinking it something with the carb, but then again, I don't know much about these machines.

[1of7627]

Originally Posted by justinmiller930

When riding around the yard, it spits and sputters during operation with the throttle pushed in.

Do your really mean, "with the throttle pushed in" or do you mean "with the CHOKE pushed in"?

The characteristics you describe are classic "dirty carb" symptoms that can result from several causes, usually bad gas or dirt in the carb (especially now with ethanol fuel that absorbs moisture), and result in a lean condition that causes the spitting and popping you experience. The choke circuit provides additional fuel outside of the carbs main functions and will often allow an engine with a dirty carb to run somewhat better.

First thing I'd try is to drain the tank and carb float bowl and fill with fresh fuel with some of one of the common cleaners (SeaFoam, Gumout, Chevron Techron, etc.). Then run the engine for a length of time. This sometimes works if the conditions aren't too bad. In my experience, I've usually had to disassemble the carb and manually clean the internals. Fortunately, carb work on these models isn't any more difficult than the larger Sportsmans. - MarkC

[spidey]

Is your battery ok? I had the same issue last year when my battery was stone dead. I could start it with the pull rope and it idled fine, but when I went to give it some gas it would sputter and die unless you let off.

If you dont enough battery life I dont think the fuel runs right. IM no mechanic, but as soon as I got a new battery or charged the old one up, it ran fine. But as soon as the old battery got discharged again, the problem came back

[cxcmoto]

If it wont run unless you hold your thumb on the throttle a little, then the throttle cable is probably out of adjustment. Inside of the throttle mechanism on the handlebar, there is a safety switch to prevent a wide-open throttle in case the cable breaks. If it gets out of adjustment, it wont start unless you touch the throttle. Pop the cover off with a small screwdriver, look for the place where the 2 wires touch at closed thottle. Adjust the cable until they are just barely apart.

Or stick a small piece of duct tape in between them to test.

Its a 5 minute fix to get it right.

Now, the spitting and sputtering is a different issue.
Carb clogged or dirty, bad gas, valves out of adjustment/ cam worn out?

How many hours on this ?

[justinmiller930]

Not many hours at all, it only has like 800 miles on it. I have no idea how many hours are on it. I think the problem lies within the carb. I'm going to put soem stuff in it to clean it out and see what happens. It def can't hurt.

And this problem has been occuring when driving under normal conditions, without the choke on (someone had asked that question). I've had the same gas in there since this summer because I haven't used any of it.

The battery is fully charged because it's on a charger.

[1of7627]

Originally Posted by justinmiller930

I've had the same gas in there since this summer because I haven't used any of it.

This is where most problems originate. With the advent of fuels with ethanol, I make it a point to not leave untreated fuel in anything for months at a time. There are several good treatments/stabilizers on the market. (Stabil now has one now that's been formulated for ethanol fuels) and they're a must if your machine has to sit for extended lengths and can't be drained.

I'm betting your machine will be okay once cleaned out a bit. - MarkC

[SMP63]

Originally Posted by justinmiller930

. I've had the same gas in there since this summer because I haven't used any of it.

This is the probably the problem!!! Get the old gas out & some new in, then see how it runs! Allot of us here use SEA FOAM gas treatment. You might want to give it a try!!!!!!!!!!

[justinmiller930]

Thanks for all of the help guys. I'll get something to clean the carb out and get some Stabil or a similar product to clean it out. I try to go out to the garage at least once a week and run it. This is the first time that this has ever happened.

[macka]

Sea Foam is the cleaner Stabil is the fuel stabiliser. Another trick is to only fuel it when you want to ride it lots. I have a 1 gallon emergency can I put 5 bucks into and a bit of Stabil just put about 1/4 of it in when I am going to do a quick ride just to get out. I carry the rest just in case, but when I am done, whatever I don't use I use in my mower or snowblower. I even will dump it into the mixing can for my outboard when I go fishing. That way I always have fresh gas with stabil in my machine. For longer rides I add SeaFoam when I fill the tank. I like to think of it as preventative maintainence.

[justinmiller930]

Where can these products be purchased? I'm familiar with Stabil, but not Sea Foam. I'm guessing at any autoparts store or Walmart?