Originally Posted by fruitbat
hi locozodiac.... my engine is a mariner 9.9 hp
Mariner 9.9 same as 15 HP could be a disguissed Yamaha or Tohatsu and both have different heights factory recommendations.
If it were a disguised Tohatsu (shaft acceleration ) the parameters are 30 to 50 mm, if it were a Yamaha (cable acceleration) the parameters are 0 to 25 mm. Both have different exhaust forms, angles, legs. Using a measurement tape measure your actual height bottom transom to anticav plate height, see if inside parameters. Are we talking about a short shaft engine ?
Test on calm waters and see for yourself, if no water splash then cut. Some boats have them as pure cosmetic issues, but will depend entirely on sib's transoms heights, 38 cm ones will splash specially with Tohatsu, Mariner, Mercury, Nissan engines. 40 cm or higher will not splash a drop. Sib's transom has been raised to 40.5 cm from previous 38 cm height. Now performing at it's best, no water splash and fantastic top end speed.