High RPM's

[Walleye #1]

I have a new 75HP Mercury tiller on my boat this spring and they told me when I was breaking it in and using it the first few times out to try and gauge the RPMs to see if it is running high when running it. What should I consider high on RPMs? They told me if it was running to high to switch out the prop and bring it back to them.

[solbes]

Once you get to the wide open throttle portion of your break-in (follow manual here), take a look at how high your RPM's are when trimmed up. If you exceed 6000 RPM's, you are too high and need a prop with more pitch (assuming you have a 4 stroke EFI). If you have an Optimax, the max RPM's are 5750. Similarly if you are lower than the max RPM' by more than 300 or 400, you might want to consider a prop with lower pitch to increase it towards that max.

[Kyhl]

Without a gauge you will be guessing.

I wonder if you could rig a gauge of some sort until it is set correctly.

[Walleye #1]

Solbes

That helps alot..