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Discussion Starter #1
hi i have an 1991 indy 500 with wiseco pistions in it i installed them over the summer and now that theres snow on the ground they are finally kicking in the sled runs great and every thing its just now when i let off the throttle the sled sounds like its running really lean and takes a long time to go back to regular idle speed? is this ok or is it too lean and how can i fix it ? all seals and gaskets are brand new and the carburetor oots are brand new ( i just dont want to do any harm to the engine because i bought it brand new cylinders and the wisecos both installed at the same time i spend around $800 for the whole top end lol i only paid 200 for the sled please help with this idleing problem oh and my sparkplugs are a little white
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High idle can be helped by turning in the air screws a bit. Usually 1/8 to 1/4 of a turn in will richen the air/fuel at idle enough so that the idle will go back to normal.

White spark plugs can be two things; too small of a main jet or jet needle adjustment is too lean. To determine which yours has, you should test the sled at wide open and at half speed. Do a run at wide open for about a half mile, and without taking your hand off the throttle, kill the engine and coast to a stop. Pull the plugs. Plug color will indicate if the air/fuel is rich (black) lean (white) or just right (cardboard brown). After you get the right main jet in the sled, do the same run at mid throttle. If the plugs are white, you will need to move the E-clip on the jet needle down a notch to raise the needle so the mid-range air/fuel is richer. If they are black, move the E-clip up a notch which lowers the needle, making the mid-range air/fuel leaner.
 

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Discussion Starter #3
ok earlier today i bought jets and needles for it the jets are 285's it has 270's in it right now ill put the 285's in it tomorrow and see if there is a difference would turning up my oilpump help also ? and can wiseco pistons handle it running a little lean?
 

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Adding oil actually makes it leaner. Weiscos are forged and a bit stronger, but no more or less prone to heat damage than OEM pistons. I'm sure the jump from 270 to 285 will make a lot of difference in plug color. Get the main set first, then check the midrange via the needle.
 
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