Bought a 1992 yamaha 4 stroke, 9.9 HP, having a Prestolite Model HYA-5110 single side cylinder tilt and trim unit. Tilt pump and or ram must have an internal leak, as it slowly drops the outboard from full up position downward at rate of approx 1 inch on tilt ram about every 10 minutes. Electric motor and pump on the tilt unit works OK, both up and down. Can anyone provide a schematic of hydraulic system in this tilt unit ? Is a seal kit available and where may I get it ? Where should I look for the cause of the leak ?
