1998 Mercury 9.9/15HP 4-stroke outboards factory service manual, Page 343Get this manual
TILLER HANDLE
8Position locking tab washer into respective tab slot and hole
aLocking TabsTab SlotTab Hole 9Rotate throttle twist grip back to full counterclockwise (wide open throttle) position10Adjust cable lengths using jam nuts to bring match marks into alignment, make adjustments to lower cable first11Remove slack in upper cable by adjusting upper jam nutsDO NOT OVERTIGHTENaUpper Jam NutsLower Jam Nuts 12Rotate tiller throttle handle from idle to wide open throttle to idle againVerify match marks are in alignment18(3.175mm)]Readjust jam nuts if marks are not alignedFRONT SHIFT MODELS 1Rotate the tiller twist grip to full counterclockwise position