RPM Question on a 1986 25 XD Outboard

[vmcts]

I have a digital photo tach. Is the engine rpm the same as the prop rpm? if not, where can I measure the engine rpm using my photo tach?

Thank You

 

[Faztbullet]

Re: RPM Question on a 1986 25 XD Outboard

Is the engine rpm the same as the prop rpm?

No as the propeller rpm is changed in lower unit by gear ratio (2:25:1)

where can I measure the engine rpm using my photo tach?

At the flywheel.....