Troubleshooting xc 500 - Page 2 - Snowmobile Forum: Your #1 Snowmobile Forum

99Polaris500 · 12-28-2012, 04:19 PM

Cleaned the carbs and everything looked fine. The was gas built up in the left hand side, just on top, so I got that out and got it running again.

After running for a couple minutes it slowly started to idle lower and lower until it was at 200 or 300 rpm. I turned the gas off again, just to be safe for now.

I'm assuming the only way I'm gonna be able to know that it's fixed is if I let it sit overnight with the gas open?

**BC_Dan** · 12-28-2012, 04:58 PM

If you are getting excess gas on one side when it's running, that side has a problem. It could be the inlet needle/seat or the float needs to be adjusted. Something is allowing the gas to over-fill the float bowl and it's running into the crankcase, which causes an over-rich mix on that side and loss of power and RPM.

When you cleaned the carbs, did you remove the float and the inlet needle/seat from the carbs?

99Polaris500 · 12-28-2012, 06:01 PM

Removed float to blow air through

99Polaris500 · 12-28-2012, 08:42 PM

I was hoping there was something just stuck in the carb, but that doesn't seem to be the case.

Whats my next step?

meburdick · 12-28-2012, 09:05 PM

Is the float arm adjusted correctly?

**BC_Dan** · 12-28-2012, 09:14 PM

Remove the inlet needle, it's likely the tip has some damage and isn't making a good seal. To remove the float, I use a small nail set and tap gently with a very small (2 oz) hammer. The pin may only go out one way, look at both ends and it should be evident. Be gentle, if you break the tangs the float is on, you get to buy a new carb body.

I'd just replace the needle/seat. If you get the viton-tipped ones, they do a better job of sealing over time.

99Polaris500 · 01-05-2013, 12:44 PM

Bought a new needle/seat. They rob ya for this little part. $55 for a plastic float and the tiny needle/seat.

meburdick · 01-05-2013, 12:53 PM

You bought new floats too? By the price, I'm guessing you went through the stealer.

99Polaris500 · 01-05-2013, 04:36 PM

Can't by the needle/seat without the float, it comes together.

Just curious how you tell that the needle/seat is bad by looking at it. I looked it over and it seems fine, and functions like the new one, but my sled runs good again so far with the new part.

meburdick · 01-05-2013, 04:46 PM

I've never heard of having to buy them as a set. Interesting.

You can't always tell by looking...

Polaris650freak · 01-05-2013, 04:50 PM

Best way to test needle and seat is to blow through the fuel inlet and open and close the the needle by move float up and down, if you get a lot of blow by with it closed than they would be bad.

meburdick · 01-05-2013, 06:47 PM

The BEST way to test is with a vacuum / pressure gauge and apply pressure to the fuel inlet line. If it holds a few pounds of pressure for a minute or more, it's good.

Polaris650freak · 01-05-2013, 06:50 PM

^very true. But not all of us have a tester!

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meburdick · 01-05-2013, 06:54 PM

Nope. We don't.

But any other way of testing is very difficult to get accurate results. So, spend $100 on a good tester, or just buy new needles and seats every few years or so.

Polaris650freak · 01-05-2013, 07:05 PM

I've only bought one set of new needle and seats in my whole life. And that's because they didn't come with them lol, so IMO I don't need the tester.

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Polaris650freak · 01-05-2013, 07:07 PM

Btw did you ever get your "power wheels" sled Dolly's? Your lucky to have won those

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meburdick · 01-05-2013, 08:09 PM

Yes, I did get them the other day. I just put them together today, and that was a bit of a PITA. I plan to try them out in the next week and will do a review on them.