# 4 wheeler engine question and help please...



## MSG Rude (Oct 6, 2003)

Folks,
I have a 2008 (I think) Polaris Sportsman 500. It will start and idle but when I apply pressure to the thumb accelerator, she bogs down and almost dies. No amount of working the throttle will get it to move, she does bogs out and dies. 
I have replaced the fuel filter and it worked great after that, I parked it, and now I can't get her to go. I did empty all the old gas out of the tank when I replaced the fuel filter.

Thoughts?


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## Sasha and Abby (May 11, 2004)

I have the same in a 2013 model. Mine was not running as rough as yours, but not smooth... Sounds like the same thing... I ran SeaFoam thru the gas and it cleaned all the crap out of the carb. Runs like a scalded dog now...


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## Kelly Hannan (Jan 9, 2007)

how much free play is in the throttle lever. There is a safety built into it that will shut engine down if throttle malfunctions


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## MSG Rude (Oct 6, 2003)

Kelly Hannan said:


> how much free play is in the throttle lever. There is a safety built into it that will shut engine down if throttle malfunctions


None. It is the same as the day I bought it. I had put seafoam in after changing the fuel filter and adding new gas also.


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## walleyecandy (Aug 6, 2012)

Is it fuel injection? If so, there is at least one throttle position sensor -probably two.

If not- take the air filter completely out and off, look for a blockage of some kind. Run it with the air filter off- just don't go anywhere dusty or dirty.

If it ran well after changing the fuel filter, but now doesn't -everything does point to bad fuel, I would check for line kinks or any other obvious problems. Once that is obviously not the problem -I would replace all lines from the tank to the carb....

Also, the overflow line sometimes plugs- unscrew the gas cap, listen for a hiss of sucking in air-while running. ...


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## walleyecandy (Aug 6, 2012)

looks like the throttle position sensor should be at or near 3.98 volt.... You can do that yourself if you have an ohm meter or bring it in.

Good luck.

If it is just carburetors- a good rule is fuel, air, spark..... Setting multiple carburetors is a gigantic pain! But beats paying someone to do it.


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## dakotashooter2 (Oct 31, 2003)

I'd bet on carb issues. My outboard was just doing the same thing. started and idled fine in the test tank. Try to apply throttle and it would die. Took to my uncle for cleaning and he found needles stuck in 2 of the 3 carbs. I generally run the engine dry of fuel to keep this from happening but it still does. Ethenol fuel is crap...especially in small engines. My uncle has a small engine repair shop. probably 75% of the work he does is carb related. Sometimes sea foam will help but it works better for preventing such problems than fixing them. I let my outboard idle for 1/2hr with seafoam in the fuel and it didn't fix my problem.

Note that in the bigger towns there are still some gas stations that sell fuel without ethanol. If it's available use it.


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## walleyecandy (Aug 6, 2012)

Ethanol is great- IF you use it right away! Otherwise all it does is draw in water, whether humidity or otherwise. ... Water and gas makes a mess.


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## alleyyooper (Jul 6, 2007)

Probably best to remove the carb/s take apart and soak in the carb cleaner of your choice. Blow out all passages I like to run pipe cleaners thru as much as I can. 
If you run gas with ethanol add stabil when you store the machine and make sure to run some thru the carb/s too.

Here is a list of ND stations that sell ethanol free gasoline. Make note that most is the premium pump that is ethanol free.

http://pure-gas.org/index.jsp?stateprov=ND

You can go to this site and plug in your state to find stations in other states.

http://pure-gas.org/?stateprov=NC

 Al


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## MSG Rude (Oct 6, 2003)

Thank you for all the help and suggestions. I will try taking it apart again and cleaning it out. I appreciate the info.


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## Plainsman (Jul 30, 2003)

I bought a Hornady Ultrasonic cleaner for cleaning brass. I rarely ever use it for that, but it sure has come in handy for other things. I had a Honda lawn mower that didn't want to run. Two cycles in the ultrasonic and it runs like new. A 9.9 Johnson outboard cost me $160 to get the carb cleaned at the dealer. It rarely gets used so it was acting up again. Six minutes in the ultrasonic has it running perfect.


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## MSG Rude (Oct 6, 2003)

Finally got around to attending to this. Thanks to you folks and YouTube, I was able to fix it myself. TPS was bad. 150.00 bucks later and it was running like a champ.

Thanks.


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## Sasha and Abby (May 11, 2004)

How'd you fix it??


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## blhunter3 (May 5, 2007)

Remember when you add seafoam when you put it away, run the motor for 5 minutes.


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## walleyecandy (Aug 6, 2012)

Good to hear it's working for ya! With fuel injection -it's usually not injectors that are the problem. Unless it sits too long with ethanol or you use the hell out of it and run hundreds of gallons through- hard to do when a 500 can legitimately get 15-25 mpg trail riding. ...

I don't have a bottle close by but- Johnson Evinrude makes fuel stabilizer that is excellent. It's not cheap but really works. I don't use Heat- Stabil- or Seafoam...

And yes- I know that your issue was TPS, but that was my first guess! Haha. I've had that same issue, mine was because a wire was broken in the TPS connection -a continuity tester isolated that luckily.


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## MSG Rude (Oct 6, 2003)

Sasha and Abby said:


> How'd you fix it??


New TPS.


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