1999 Indy 500 Idle Problems

[crzytoad75]

A friend has got a 1999 Indy 500. It will not idle at all. As soon as you let off of the gas, it will just die. He can give it gas to keep it running and runs great at WOT. I've went through the carbs and everything was spotless. Main jet and pilot jet were all clear and no restrictions, needle and seat will hold close on pressure also. It was running fine until the end of last year when he was doing some drift busting on the second to last trip. Gas tank was drained and fresh gas was used. We're kind of at our wits ends as to why this thing would go from running perfectly to not idling. Any ideas or thoughts as to which way to procede will be appreciated.

[dcorazal]

Sounds like your on the right track. I would recheck the pilot jets use carb cleaner and blow compressed air in the pilot circuit. Also could be an air leak in a seal (carb boot, pto clutch seal, base gasket, etc.)

[The Hunter]

Is your throttle adjusted correctly. I believe 0.030" between the block and throttle is the norm. This will allow proper activation of the throttle safety switches. Have you tried running it with the switches and kill switch unplugged?

[crzytoad75]

We've kinda been leaning towards something in the carbs, since it's usually the culprit. I doubt if he's checked the cable and throttle safety. Though would the throttle safety only bother the motor on idle only? It'll run fine other than idle. I thought that the throttle safety was for wide open or close, not idle. Thanks for the replies.

[framer__]

I would clean the carbs sounds like the idle circuit has some debris in it. That or the throttle freeplay like "The Hunter" said

[switch06]

sounds like too much free play in throttle cable and throttle switch is killing engine. free play should be about the thickness of a nickle, in other words you should be able to put a nickle between throttle lever and block, if its more than a nickle there in too much free play and cables need to be adjusted.

[fez]

QUOTE (CrzyToad75 @ Feb 25 2010, 02:51 AM)

We've kinda been leaning towards something in the carbs, since it's usually the culprit. I doubt if he's checked the cable and throttle safety. Though would the throttle safety only bother the motor on idle only? It'll run fine other than idle. I thought that the throttle safety was for wide open or close, not idle. Thanks for the replies.[/b]

If the throttle safety is gone bad or sticky it doesn't know the difference between WOT and 1/64th throttle. If you can keep it running with a cunt hair of throttle but the second you let off it dies, then it is more than likely the throttle over-ride.

[framer__]

hahahaha a cunt hair of throttle

[crzytoad75]

Thanks for the replies guys. Ended up adjusting the throttle cable with no luck. Took carbs into local dealer and had them pressure tested for bad needle/seat, held pressure. Dealer didn't even charge us anything which was a very nice change of pace. He suggested adjusting the choke plungers. I adjusted them so that the cable wouldn't pull them up, no luck. Finally said screw it and turned the idle adjustment screws in until it idled. Ran fine the whole day. Get up the next morning only to find the water pump bearing had went and was spraying anti-freeze all over the place. Later that night another guy in the group with an Arctic Cat broke his clutch bolt and sent the primary into the belly pan for some pin ball action. What a weekend..... put on over 300 miles though even with all the wrenching and waiting for the truck and trailer to come.