I have a 2001 Polaris Scrambler 90 that my son rides. The machine sat for around 3 months this past winter. I did not use a fuel stabilizer and in my area we have the reformulated garbage gas. When I pulled the machine out this spring it fired right up. I topped the fuel off, added injector oil, lubed the machine up, and checked air pressure. My son took it out for a ride and I noticed that he appeared stalled about 150 yards from me. I walked over and asked what was wrong and he said the machine keeps wanting to die. I goy on and the machine took right off, but after hitting wide open throttle the machine started to sputter and back fire and basically die out. If I let off the throttle the machine idles just fine.
Now I assumed that I had a simple carb cleaning issue as I was sure that the jets were gummed up or plugged. I took the carb off and proceeded to clean. As I figured both the main and the pilot jet had a hazy film covering the holes. I cleaned them and all other areas of the carb with carb cleaner and reassembled. All seemd fine after reinstalling the carb, but then 10 minutes later the same thing happened. Again I disassembled the carb, but this time I could not find anything anywhere.
I have taken the carb off the machine now a total of 21 times in the past week and I cannot get this machine to run at open throttle. I changed the plug, checked the electronic choke, changed the fuel filter, drained the fuel and replaced all fuel lines. Still the exact same problem!!!! The machine starts and idles great. At 1/4 to 3/4 throttle it runs OK with a slight hesitation occasionaly. At full throttle it runs for a few seconds then starts sputtering and bogging.

What I am asking for is help. If anyone knows what it may be please let me know. I also need to know what the factory setting for the airscrew is. I adjusted mine and before doing so I screwed it all the way in counting the screw-driver turns. I had only a 1/2 turn to closed. Does this sound right?
Any help on what I am missing would greatly be appreciated.

Oh yeah, I do notice that at idle or throttle the carb seems to spit or mist a good amount of fuel out the air inlet side of the carb. This does not seem normal to me. Please feel free to email me at lisnup65@yahoo.com for more info if need be.

Thanks in advance,
Dave

 

Clean your flywheel coils and pick up. Check all connections for loose or dirty pins. Air screw at 1 1/4.

 

Could you possibly explain the reason for the flywheel and pickup cleaning? I have checked all connections already. I even dielectric'd them to ensure a solid connection. Are you sure the airscrew on the inlet side of the carb should be at 1.25 turns out. From new mine was only .25 turns out. Do you happen to have a service manual you are getting this info from?

 

I have had some problems with my sons 02 SPORTSMAN 90 with the carb not wanting to idle when cold or hot.I found 2 problems that my dealer could not find,the first being the stator was bad not letting voltage get to the electric choke to keep it engaged when the machine was cold.The second problem is that the pilot circuit in the carb does not let enough fuel thru to keep the motor idleing.The dealer replaced the stator after I had to pound it in his head to check the stator voltage output per several post I read on another forum.As far as the pilot circuit in the carb a small drill bit just a tad bigger than the fatory hole solved this problem,but the sad thing is that POLARIS knows about the starting problems with the 90 cc machines an even changed from an electric choke to a manual on all the 2003 models but they will not recall the older ones to fix what they no was a bad design on the carb to begin with.

 

This engines were designed for scooters. The air intake for tyeh fan will suck up water and mud and it will get inside the stator and all over the flywheel. THe coils will go bad from heat and the sensor will start missing from just trying to work through a layer of dirt. The air screw information is from the best source. ME. [img]i/expressions/face-icon-small-wink.gif[/img]

 

yuck!!!!!!!!!!!!!!!i just bought my son a sp90,,,'02 new. i personally dont like the choke thing and ill prodably redo it ith a conversion kit if there is one. tell me are these 90's junk? or are there just a couple of bad incidents that im reading???[img]i/expressions/face-icon-small-confused.gif[/img][img]i/expressions/face-icon-small-sad.gif[/img]

 

I certainly don't think the mini's are junk, but did we ever get the not running wide open problem fixed?

 

First off, thank you to everyone that offered suggestions and help.

To update for everyone.
The problem appears to be resolved. I took the carb off for the 27th time and cleaned again. I checked the choke and it seems to be working fine. I cleaned the stator and all contact points. I die-electriced all connection points in the harness, replaced plug, die-electriced the plug wire, checked head bolts, and beat the shiet out of the quad just to releive frustration(JK!). I reinstalled the carb disposed of the metal clamp on motor side and replaced with heavy duty removable zip tie, replaced air filter.

Machine starts fine and it now runs like it is supposed to. I was still getting sputters on occasion, but the air screw fixed that. My machines air screw adjustment is about 1/4to 1/2 turn out from bottomed out position. The plus looks nice and tan after an hour of riding by my boy.

I have an issue with the float level now. Its a little out of adjustment as it allows a small amount of fuel to drip from the overflow when the machine is not running. Does anyone know what the measurement should be and where to take it from so I can readjust to spec.

Again Thanks to all with input.

 

I would check your inlet needle to veryify that it isn't worn and causing leakage. To check this you will need to once again open the carb and pull out the inlet needle, hold it up to the light and it should have a smooth surface where it makes contact with the seat, if it is worn it will have an indentation all the way around it, needle and seat is probably $10.00 at the most. might be to your advantage to go ahead and replace it when you check the float setting. The e-mail I sent you explained how to set the float, it should shut off the fuel when the float is level.


Good Luck

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just bend your tab up a little it is located in the middle of your float