2002 yamaha sx viper fuel supply help

Bigyamaha87

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Dec 12, 2021
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So i replaced the inline tank filter and and hose now the sled will start but hardly idle, like its not supplying enough fuel and backfires and eventually dies. Until you flip the choke lever then it comes back to life. I put a brand new fuel pump on still the same. sled idled great and ran fine untill i changed the filter. Any suggestions, Im pulling my hair out.lol
 

The first thing that comes to mind is that the carbs need cleaning as its acting like it has dirty/plugged pilot jets.
Because you were working on the fuel supply some other thoughts:
-low on fuel
-water/ice in fuel
-cracked fuel fitting
-fuel supply filter in the tank is too restrictive
-fuel supply filter is not in proper position at the bottom of the tank
-fuel supply lines are cracked or not tight and sucking air
-kink in fuel line
-fuel pump pulse line is cracked or connector leaking air
Check routing, connections, and proper position of all fuel lines to pump and carbs
 
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Weird part is i just did my yearly carb cleaning. Sled ilded and ran great. Then i decided to chage the in tank filter and started it back up with a full tank of fuel now it runs like crap.
 
If the sled is out in the cold bring it into a heated garage over night and see if conditions improved.
The original SX Vipers had an issue of the fuel pumps freezing up...the fix was increasing the space between the base of the pump and the tunnel as well as plugging the vent hole on the under side of the fuel pump.
 
Float bowl needle valve setting? Or maybe one of the floats is stuck, or the needle valve gummed or or got some debris in it? The adjustment of the float height is somewhat sensitive and there's a procedure to get it set right, maybe that is off? TORS on my SRX will make it run funny instead of kill it like on my phazer, maybe that's your cause? Brainstorming some ideas...
 
Thanks for updating....good you figured it out.
The screws on the bottom of the carbs on these sleds are fuel screws and control the idle/low speed fuel supply to the pilot jets. Screwing them in leans the mixture and screwing them out richens the mixture. 1 1/2 turns out is a good starting point.
 


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