Amazon Secure Payment System Continue shopping “Idle Adjustment Knob & Retaining Ring – 9.9 & 15 hp – 1974 to 1985 – Johnson Evinrude – OMC 387272” has been added to your cart. Product Price Quantity Subtotal × OMC STERN DRIVE, 1964-1986 Repair Manual $26.95 OMC STERN DRIVE, 1964-1986 Repair Manual quantity $26.95 × Idle Adjustment Knob & Retaining Ring - 9.9 & 15 hp - 1974 to 1985 - Johnson Evinrude - OMC 387272 $25.82 Idle Adjustment Knob & Retaining Ring - 9.9 & 15 hp - 1974 to 1985 - Johnson Evinrude - OMC 387272 quantity $25.82 Coupon: Apply coupon Update cart Cart totals Subtotal $52.77 Total $52.77 Proceed to checkout