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Discussion Starter · #1 ·
I just put a new motor in this sled. both carbs are clean and are the same carbs I used last year with no problems. The engine idles perfect but as soon as I touch the throttle it flat out dies unless I flick the choke on quick. After about 2000rpm the engine runs perfect. I realize that because I need to use the choke,the engine must go dead lean upon throttle input. But why? how? The fuel pump appears to be working correctly. Starts on the first pull usually. 120 psi in each hole. Slides are moving in sync. Oil pump is timed right. I did add oil to the fuel but at a mixture of 75:1 so I wouldn't think that would matter.

I'm at a loss here. Any ideas? Thank you.
 

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You mentioned the carbs are clean. Are you positive? My '90 500 did the same thing last year. Was running just perfect. Then all of a sudden she started the same thing you are experiencing. Turned out to be dirt in the pilot circuit. The carbs were about due anyway, so I tore them completely down and cleaned them. Has ran perfect since.
 

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Discussion Starter · #3 ·
I could look again, but I've had them apart 5 times this weekend for various reasons. It's possible something came from somewhere when I was screwing around the last time. The pilot jet seems like the only logical explanation. Unless I'm missing something else.
 

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How did you set up the carbs? 1.5 turns of the air screw? That kind of thing. Airbox hooked up properly, with no leaks? Probably just a setup issue with idle screw/air screw adjustments. Not the same circuit, but a needles set at same ring as before?
 

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Discussion Starter · #5 ·
Well I tore the damn things apart for the sixth time tonight. Every thing was clean. took all the jets out. sprayed carb cleaner through every orifice in the carb bodies as usual. Drank a beer and stared for awhile. Lowered the float level about 1/2 millimeter in one carb because the tab looked a little bent. Drank another beer. assembled the carbs and reinstalled. Pull,pull,pull,pull,choke,pull,pullpullpull,"WTF?" Oh yeah, "TURN THE GAS ON DUMBASS!" pull,pull and fired right up. runs perfect. Couldn't tell ya what was wrong but it runs great now. I'm so relieved. Just a few more stupid little things and I'm ready to kill it all over again. Thanks guys!
 

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it is running now but, Did you check the throttle safety switch.?? You know the 2 little pins right in the throttle lever. If the cables are not adjusted just right, it will die as soon as you touch the lever. They could have got out of whack when you put it back together.
 

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Discussion Starter · #8 ·
Thanks lurch77. I hope she holds together this time. Dutchman, This is why I love this site. I completely forgot about the safety switch. I don't think that was the problem but now that you mentioned it I'm going to make sure it's working. NOTHING sucks worse than a stuck throttle on a runaway sled. You guys rock.
 
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