How to measure a Long Shaft Mercury Motor

[PeterInSA]

Hi, Where do you measure from and to,. for say a 20Inch Long Shaft Motor?

Are there various long shaft sizes?

Thanks

Peter

[Noelm]

Simple, just measure from the lip that would sit on the transom, down to the cav plate, they make/made 15/20/25/30 inch models depending on HP

[GBC]

Shaft length matches transom length (should). Measure from the point where the transom bracket sits on the top of the transom to the bottom of the cav plate to give shaft length.
depends on what h p you are talking, but most larger 130hp+ would be xl (25") legs. Long shafts (20") are more common on tinnys bigger than car toppers.

[kizza1]

The mercs tend to add 1 to 2 inches to eliminate cavitation on some boats so your 20inch longshaft from under clamp bracket to cav plate will actually measure 21-22 inches