99 polaris indy 500 fc too rich on bottom - Snowmobile Forum: Your #1 Snowmobile Forum

classics2go · 11-08-2012, 05:51 PM

I have a problem with a 1999 Indy Trail with the 488. The story from the previous owner was that the sled would run great then loose power and idle fine but would not go. Since then it has been stored. I did a full service on the sled and found the worce chaincase oil I had ever seen. It had turned into some sort of varnish. Guessing it had gone swimming at some point. After rebuilding the chaincase, going threw the carbs and fuel system...I had it started. It was not running well.. I pulled the pipe and found a mouse nest inside. Started it up again. Seemed to run fine. The next day I was getting ready to move it out of the shop when it started bogging. I got it on the stand and revved it...runs great in the high r's... but at idle it is loading up big time. I pulled the carbs and checked float heights and made sure the floats worked proper and are free. Still no change. The sled does have egts and they are both cold and may not be working. It has an aaen single pipe. Carbs set 3/4 turn out. 250 main, 20 pilot. Clip at mid setting. It is shooting fuel back from the carbs into the airbox from idle to about 3500 rpm. Any ideas? Thanks in advance!

classics2go · 11-08-2012, 06:05 PM

Btw.. I had turned off the fuel...made it a habit w polaris... also checked the case drain and it was pretty dry.

**BC_Dan** · 11-08-2012, 11:13 PM

Try turning out the air screws to 1 turn out. That will lean out the air/fuel from idle to 1/4 throttle (if the pilot jet circuit is working properly.)

You can also contact Aaen and they should give you jetting requirements for temperature and elevation for their pipe.

classics2go · 11-09-2012, 01:25 AM

Yeah I tried leaning it there, no luck. 20 pilots sound big to me... Shouldn't it be a 15 or 12.5? Does anyone know what came stock in the twin carb 488 fuji?

Quote:

Originally Posted by BC_Dan

Try turning out the air screws to 1 turn out. That will lean out the air/fuel from idle to 1/4 throttle (if the pilot jet circuit is working properly.)

You can also contact Aaen and they should give you jetting requirements for temperature and elevation for their pipe.

**BC_Dan** · 11-09-2012, 01:32 AM

The Polaris site shows a 40 pilot as stock in the 99 trail.

Browse

meburdick · 11-09-2012, 12:16 PM

Can't offer a lot in the way of troubleshooting, but wanted to point out that your post title says Indy 500 but your post says Indy Trail. These are two completely different animals. Refer to your sled by the correct name (Indy Trail) in your post headings and you'll get more people with direct knowledge than can help.

classics2go · 11-09-2012, 02:29 PM

Wow...a 40? Hmmm... The sled does not say what it is. I was told its a 500 from the previous owner. Looks like a 488 fan to me with twin carbs and a single pipe. I will get a pic posted later tonight. I have had lots of wedge slowaris snowmobiles but this is my first evolved chassis or whatever they called it. I figured a 488 fan was a 488 fan.

meburdick · 11-09-2012, 02:37 PM

Indy 500 is a 488 Liquid Cooled

Indy Trail is a 488 Fan Cooled

Indy 440 is a 432 Liquid Cooled

Indy Super Sport is either a 432 or a 488 Fan Cooled (depending on year and motor option)

Like motorcycles, the number designator is not necessarily the exact cc displacement of the motor. It's more of a model name. The 488 Fan Cooled motor is used in a lot of different models, one being the Trail. The point I was making is that it's important to know that the "Indy 500" is liquid cooled and the "Indy Trail" is fan cooled - very similar sleds, but some key differences. Folks more familiar with the liquid cooled motors (like myself) are more likely to open your thread and try to help. Unfortunately, I don't have much experience with the fanners, so I can't help.

**RJ Gleason** · 11-09-2012, 03:42 PM

I would check and make sure that the "chokes" are not stuck open.
It is a common problem on a lot of sleds and will make the engine too rich in the low end and will lead to fouled plugs [a lot] which will cause the symptoms that you are describing.

classics2go · 11-09-2012, 09:59 PM

Tried the chokes. No luck. They move free and have no corrosion. I ultrasonically cleaned the carbs, blew them out, balanced them, etc. It does seem like a stuck choke circuit but they seem to be seating and working fine.... Stumped.

classics2go · 11-10-2012, 02:13 AM

Pulled the carbs again...triple checked everything... Pulled the exhaust again....Checked and cleaned it out once again...no mouse junk in there..nothing more came out. Used a wire to check, ran water threw, etc. I heated the water out of the glass packing with my lil turbo heater...Feels light and dry.Taped the throttle wide open and pulled the plugs to dry it out. Going to give it a shot tomorrow. Hope it cures itself..lol. If not then i think I will be hunting for 15 pilot jets.

meburdick · 11-10-2012, 08:19 AM

Where are you located? Maybe there's someone in your area that help in person.

joshkidner · 11-10-2012, 04:08 PM

bc_dan said it should be 40 stock, but i would contact aaen and see what they recomend (or look on their website and try to find it)