Dave - if it is a 2GM not a 2GM20 then you are wasting your money on a bigger shaft. The larger shaft was due to the added horsepower of the 2GM20 on the new boats. The shaft is so short that vibration is coming from other things like shaft mis-alignment, shaft ware at the stuffing box and strut, bad motor mounts, prop needs reconditioning and/or new cutless bearing. My boat has NO vibration underway and it has a new 3/4 shaft that was professionally aligned, new dripless seal, reconditoned prop and new cutless bearing. However this all was a small fortune.

David
#397

David Bows
Mallorca - Hull# 397
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