1999 Volvo Penta "WT" Models Workshop Manual, Page 7Get this manual
Model Identification
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stern drive system components must be matched for either single or dual engine installationsFailure to properly match engine, transom bracket and vertical drive will result in poor boat performance, and risk damage to engine and drive because of incorrect drive gear ratioModel identification is located on the engine valve cover, and MUST correspond with the transom bracket and vertical drive numbers as listed in this document Engine Model Number