float and needle is fine yet still overflows and floods---The fix

[Freezeman]

Thought i would share a fix that I came across. I was working on a 99 scambler 500, The customer complaint was that even with the fuel shut off the tank would slowly drain out onto the ground. First I found the fuel shut off was bad/ leaking/ dripping so I installed a new one thinking that would fix it. Then I ran it and and seen that the overflow was flowing fuel out from the bowl. So I cleaned the needle and seat and changed the float height to lower the fuel level in the bowl. Well... It still overflowed and flooded. So I bench tested the needle and seat with a pop off tester. I found that these newer style needle and seats just utilize an o-ring to install the brass seat into the carb.

The o-ring for the seat had hardened up allowing fuel into the float bowl from under the seat. New o-ring and problems solved.  

 

  

[Frank Angerano]

@Freezeman that’s some good info. Some of the needles have a rubber tip on them as well.   Sure you will save someone a lot of float adjustment time after reading this.   

👍🏻

 

 

[Freezeman]

I got another 2013 sportsman 500 with 960 miles on it  with the air filter box and motor full of fuel. The same leak from behind the needle and seat. This poor design has to be causing lots of grief to Polaris owners. The owner had found the air box full of fuel and leaking all over his garage floor the next morning after a ride, he was lucky that it didn't kill anyone with a house fire.

He cleaned it up and then tried to start it. It would not crank as it was liquid locked so he thought he needed a new starter after he replaced the battery.

[Frank Angerano]

So it was the same exact issue as the other one you fixed ? 

[Freezeman]

yes, Booth were Mikuni's with the plastic rack for the floats that set on the rim of the needles seat and the seat is just plugged into the carbs body with an o-ring. The seat is loose because the o-ring has shrunk or is too small to begin with. I didn't order a new OEM o-ring as the same problem would probably happen again, I just use a o-ring from a Metric Harbor freight o-ring set that is a bit larger which requires the seat to be pressed in hard and stays put with out the plastic float cage holding it up in the carb body.

[Frank Angerano]

I love it, great info on this. You would think that this would have been a bigger issue with Polaris and complaints as well as a fix   

Having that  o-ring set is very handy as well.  

Good stuff brother.   

 

[BuggyMasters]

Have seen this a few times. Good catch.

[Laval]

This happened with my Yamaha as well. A five cent o ring is the fix.