Hi, I have a 2004.5 SP 500 HO. Gas has leaked from the carb drain in the past mabey 50 hrs or less ago so I replaced the Needle and seat and that fixed it. Well now I have gas just pouring out the carb drain hose on the bottom again. Pull the carb apart and bend the float tab up on it, no fix. I have bent it all the way down and all the way up and gas just keeps pouring out. I did notice that the "seat" part slides up and down in the cavity that it sits in so I figured that gas is getting by the seat part and not the needle. I then decide to put gasket sealer on the seat so it stays in place better. Put it all back together and leaks just like before.....Question: is the seat suppost to be able to slide up and down in that cavity????? I am about ready to buy a new float and needle and seat. The needle has a ring towards the top of the point so I think that is seating tight against the seat.
Any ideas? A float is 40 dollars!!!

 

Are you sure that your float actually "floats"? Take it out and shake it to see if it has a hole in it and has gas inside. Also - I think you're confusing terms here - the needle is the triangular shaped piece that slides up and down in the "seat". You should NOT have a ring around the top of the needle valve as that is a sign of wear and maybe that is why you have the leakage. Generally, the seat threads into the carb body and has a gasket or seal - is yours missing?

 

Yeah, the 100 times i have taken it apart there is never gas in either of the two floats. My terms are correct I probbably explained it poorly...lol...When I take the seat out not the needle it just slipps easily in and out of the carb body(there is an oring on the outside of the seat to seal to the body of the carb)...when I bought a new one it did the same thing....All I have done is make it so the seat can not move in the carb body with sealer....the needle does have a ring around the top like the old one did i guess....but it is pouring out so fast that if it was worn it would just be a little dont you think?
No thread or anything to hold the seat in, I think the parts of the float push against the seat when the bowl is installed.
Thanks!

 

This is the carb that replaced the earlier version. I dont like the float assy versus the 2 individual floats and how it supports the needle and seat,hard to adjust to keep them from dripping even a little bit,plus almost ALL eventually break the spring on the bottom of the carb that holds the idle adjuster. You cant even get the older carb assy,it supercedes to the BST40. All I can say is I have played with em and even ranted to Polaris and almost all do leak a little from the overflow no matter how you try to adjust this carb. OPT

 

Yeah i agree about the older style carb being much better for sure!!...The problem is that it is not a drip or two it is running a puddle under the machine in 10 sec....somthing is out of wack, just dont want to keep putting money in when I dont know exactly what to replace, I would think needle and seat but that was replaced 25 hrs ago....gets to be spendy per hour of use....any ideas on it?>?? Thanks OPT.

 

A little bubbling and a small amount of dripping is kinda normal,but a puddle is not! If tang is bent too much on the float can cause problems. Also check float bowl with gas almost up to the top to see if overflow tube is cracked (can happen). If ok and not leaking then might have to try a new float assy. OPT

 

I had the same trouble with a 1988 Yamaha Exciter Snowmobile.
I would find a puddle of gas on the trailer all the time after using it towing it home, I rebuild the fuel pump in the sled and this fixed the problem for me.
Also when the trailer was sitting in the yard between week-ends the sled sat on a very sharp angle (tilted down-ward at the front).....This caused the fuel pump to be alot higher than the carbs were...Thus causing the pressure to over-ride the floats in the carbs.........Caper..........

 

Caper, with it being the fuel pump wouldn't the engine have to be running to make it leak out the float bowl????? Or did it leak sitting with that problem, mine is on a level surface and it leaks sitting or running. Never thought about fuel pump!

OPT: I checked the float bowl with the bowl full of fuel already.. I have the bowl off the machine and fill it full. Then no fuel comes out the tube. I have seen it as well were the overflow tube cracks (not sure why that happens!)

Possible issue:

Needle and seat?

Float assembly?

Fuel pump rebuild?

Machine has 320 Hrs, 1875 Miles (2004.5 SP500)

Thanks so far.

 

Sorry I just don't see this difference from the first 01 H.O carb vs the 05 H.O? especially the floats.

2001



2005

 

Mine was flowing right through the fuel pump into the carb and even filling the cranckcase with fuel.......It was hard starting and when started the raw fuel was pouring out the exhaust on to the trailer.....

With the bad diafram in the fuel pump the gas was still under vacuum and running after the machine was shut off, Thus filling the carb and cranckcase full of fuel...The angle on the trailer did not help either ,this helped to keep it flowing easy................I bought a re-build kit for the Mikuni fuel pump..
Like I said it fixed my fuel flow issue.

But it may not be the cause in your case here........Caper...