1997 polaris 500

Dirtautoguy · October 9, 2014

My soon to be father in law told me and my fiance that if we could get the fourwheeler to run that we could have it. it would start and idle with the choke on but would die soon as you gave it any gas.

Things we have done to it.

cleaned the carb

new spark plug

oil change

new air filter

After we cleaned the carb it ran pretty good for the most part it still didnt go into the high end very well it didnt seem like though it was like it would bog down. we parked it for about 2 or 3 weeks and decided to ride it a little again. and now it is doing the same thing that it was doing befor but not quite as bad. we did put some fresh gas in the tank as it was about empty. but before we messed with it it sat for about half a year is all but it was outside. The battery is completly shot and wont hold a charge but I dont think that would effect how it ran in any way would it?? any ideas?? thanks

ifixedit · October 9, 2014

When it comes to cleaning the carb on something that has perhaps sat a long time and was not given a gas Stabil treatment before it was put away, you may have to go a bit further with the carb to get it running good again. The problem with the modern concocktions of gasoline with ethanol is it's good for about 3 months and then it starts to go bad, especially when the gas is sitting in the bowl of the carburetor where it begins to evaporate, dry up and it leaves gunk and green depsosits from the mositure it collects behind.

I'd go through the carb again and take it completely apart including removing all the jets which would include both the pilot jets which controls both the idle and off idle to mid range, and the main jets which controls top end fuel delivery. Also remove the idle mixture screw, the inlet check valve, everything, in other words take it al apart so you can be sure you can clear up every passage in the carb. Take the jets out and inspect them looking through a good light, they are probably plugged, sounds like in your case the main jets are plugged since you are having top end power issues.

You don't want to push it with plugged main jets as this can cause a severe lean condition and the end result is a burned down engine with a minimum of scorched pistons and worse damaged cylinders. With the carb totally taken apart use a can of carb cleaner and spray it in all the carb passages to be sure all are clear. If the jets are plugged or restricted, get them cleaned out, if you can't get them cleared out, pay a visit to your local Polaris dealer for some new ones, both pilot jets and main jets, don't take a chance with these! New jets are much cheaper than an engine rebuild which could include piston, rings and probably a new cylinder if it burns down badly enough.

myfirstchevy · October 9, 2014

I would do what ifixedit said.

Also I know with my raptor 700 when the battery was bad it didn't want to run right, seemed like too much strain on the stator trying to charge the battery and run to engine.

ifixedit · October 9, 2014

Also, if I am correct this Polaris 500 is a 2-stroke, correct? Reason I ask is my brother owns one of about the same vintage and his is a 2-stroke. Just to add a few things, the fact it would at first run with the choke on but not with it off is a sure sign the pilot jet circuit is plugged, seems since you took the carb apart you perhaps got that part of it cleared up but if it's bogging or will not run good at full throttle your main jet circuit is still plugged. Under full throttle you can also flip on the choke, it the engine improves in how it's running, you've for sure got a plugged main jet circuit. Again, take the carb completely apart and spray carb cleaner in every passage of the carb. By all means don't ignore the problem and run it in this condition! The colder the weather gets and you run it like this, the leaner the fuel delivery gets and you're just asking for a bad burn-down.

For anyone into sleds, dirt bikes, or other 2 stroke (and now 4-stroke) performance that's interested, these two books are worth their weight in gold. >> http://www.aaenperformance.com/Handbooks.asp

keep us posted on the outcome.

SnakeEyeSS · October 10, 2014

Something simple to check and replace: Fuel Filter. A clogged filter would prevent proper flow when needed. It could be supplying just enough to get it to run, but plugged enough to allow any more through.

Hate to see you get into something complicated if it's something simple!

ifixedit · October 10, 2014

Good point! If the fuel filter has not been changed in a few years or hasn't been changed and your Polaris has been sitting a few years and has not bee ran, good idea to install a new one.

Dirtautoguy · October 17, 2014

Ok awesome, the fourwheeler is a 4 stroke and has awd. we have a new fuel filer for it but we havent gotten around to messing with it again yet. soon as we can i will post what we find out. thanks for the help

ifixedit · October 22, 2014

2 stroke or 4 stroke, if it has sat longer than 6 months with no Stabil in the system be sure all the circuits in the carb are clear first. Replace the fuel filter as suggested as they will also get crudded up from sitting with old gas in them, and you should hopefully be good to go.

Dirtautoguy · November 19, 2014

it is a 4 stroke. and it has been sitting even longer life doesnt seem to want me to work on it but im trying to get there and ill let you know what I fine.

ifixedit · November 19, 2014

4 strokes in particular have very finicky idle circuits and if there's anything at all in them it will refuse to run if even start. When you do get around to it, stop by your local auto parts store and get a gallon can of carb soaker, I know NAPA has it. Dismantle the carb as much as you can, drop everything in the basket and let it soak a day or two first.

Spurshot · November 22, 2014

Never try to diagnose a suspected fuel problem when you have an electrical/ignition issue. For a spark to jump a particular gap it becomes a much higher voltage requirement as cylinder pressure goes up. Make sure you have a good battery before messing with the fuel system.

ifixedit · November 23, 2014

I've been around small engines, snowmobiles, dirt bikes, two and four stroke (you name it), for many years and can take them apart and put them back together and diagnose problems with them in my sleep. Trust me, if it's sat for any more than a year with our great (not!) late model fuel and was not Stabiled, assuming there is not already damage to the internal brass parts of the carb, at a minimum the carb needs to be completely taken apart, all parts soaked, all jets and circuits completely inspected and verified as clear and flowing normal. Time sitting and not running should have zero effect on the ignition side of things. Most anything later than a 1976 model and we're not talking about dealing with points or other issues for the ignition to get weak or not work from sitting over time unless one of it's components (like the CD box) have completely failed, and I'd assume on the machine in question here is using a CD ignition. Being he reports it does indeed run, but runs like crap, we're talking carburation and nothing else other than the chance a pack of mice made a nest in the exhaust or the intake and either or is completely plugged up, that or the NGK spark plug is fouled and needs to be replaced. Go through the carb as I describe, inspect the air box and exhaust to be sure they are clear, and it should run like new.

idnative1948 · January 24, 2015

+1 on the above comments. The carb NEEDS to be torn down to get the crud out of the jets. I would replace fuel lines/filter and vacuum lines to save yourself some grief and they don't cost much either. Myself (JMHO), I swear by Sea Foam in our sleds and ATV.