Hi everyone. I am new to ATVs and the forum.

I just purchased a Used 2004 Sportsman 90 for my kids. It ran great at first, or so I thought and it recently started giving me problems. After the kids were riding it for the second time a friend noticed that there was no smoke coming from the exhaust and it being a 2 stroke, there should be a little. it was driven a few more times before stalling out. We took the top end off and the Cylinder and piston were o.k. We also cleaned and blew out the carb. After everything was put back together it starts o.k. but as soon as you give it full throttle it wants to stall and the choke at idle has to be almost all the way on for it to stay running. If anyone has any ideas let me know. We think its the carb, but again we cleaned out and cannot see where any of the jets are clogged

Thanks everyone for their time and any help they can offer

 

maybe something got knocked out of adjustment when you blew on the carb. check the air filter to see if its dirty and check for any air leaks. if the choke has to be on then its not getting enough fuel with the amount of air it has available to the motor. might even need a top end job. check compression then do a leak down test on it. or instead of leak down try spraying carb cleaner around all gaskets and if the idle goes up then you know there is a problem there. with two strokes its a pretty comon problem.

 

Thanks for the info. I will do the leak test and see what happens. I already checked the top end and the piston,,riings, and sleeve all looked o.k.
I greatly appreciate you taing the time to help out. I will keep in touch and let you know when its fixed and the actual cause.

 

make sure the gas tank and carb vents arent blocked or pinched as well. how does the spark plug look when you took it out? if it was fairly light to white then it was running too lean for sure. did you mess w/ the float and is it set correctly? i would do a compression check (cant tell by looking at it) to see what it has. just a few idears.

 

Hi There.
I have a 2003 Predator 90. I have checked and cleaned the following. gas tank and blew out all gas lines, fuel valve, the carb apart 3 times and cleaned everything out, the reed valves. All is very clean no restrictions. Starts easily and idles fine but will not run. It appears to be a common problem. I have seen at least 4 posts with the same problem but not answers. So if any one knows the answer please let us know.

Thanks
Richard

 

Sounds like the pilot jet has something in it, thats the small jet in the carb, remove it and spray carb cleaner through it and the hole it came out of.

 

My son has a polaris 90 as well and I experienced a similar problem... His would start up and run fine, so long as it was used often. If it wasn't ridden in like 2 weeks the thing wouldn't start. It might run really softly, and then the minute you even touch the throttle it would sputter and die.

I just used a bit of ether(starting fluid), sprayed it down the carb and started it... and carefully worked the throttle this way. This seemed to get the fuel system back and working again. And then the bike would run/start as normal... No issues.

I never got into the interals of the fuel system, just called the dealer and they said it's a fairly common issue and told me to try the starting fluid. Fuel conditioners don't seem to work either. We've tried that.

Hope this helps

Carl

 

I just had the exact same problem with my son's quad, I took the carb apart and cleaned it really well, and while I had it on the bench I took off the electronic choke and really cleaned it out, it felt like it was binding up. Put it back together and it runs perfect, my son was out for an hour yesterday. I really thought I was going to have to buy a new choke but cleaning it seems to have worked so far.

Now I just need to find a new gas tank (cracking around the rubber neck) and a gas cap.

 

Common problem on staring on the 50 and 90 Sportsmans,especially if not ridden daily,kinda hard to get fuel flowing. Hard on engine to use starting fluid,washes down oil from cylinder wall. Even on newer machines with manual choke sometimes hard to start and prime up fuel flow. One litle trick if carb and lines clean and still have trouble starting and warming up is to place thumb over air box inlet tube that tucks up under frame,this helps prime up quicker and less starter wear and cranks up quicker. Believe it or not have a tech bulletin on this. Hope this helps some of you.

 

My kid has a 90cc sportsman and it starts and will idle well, but it chokes out when you give it gas. If you work the throttle you can get it to run, but after riding a bit (few minutes) it will just choke out again. When you do get up to speed and then get off the gas it back fires horribly. Any ideas on what to do?