Spare prop negative effects??

[AWC360]

I have a 16' Boston Whaler, Dauntless with a Merc 2-Stroke 115. We recently put an entirely new lower unit on the motor due to corrosion. Our primary prop is currently being shipped to us, the mechanic put our spare prop on for use in the mean time. I've run the boat briefly and have experience some odd effects:

With the engine trimmed all the way in, the boat rides high with the bow way up. The engine is rpm'ing way too high at cruising speed. I'm hoping these will be cured with the installation of our regular prop (which I think is a bigger pitch).

Is there anything else that could be causing this? And is there ANY way the wrong sized lower unit might have been installed, is that even possible?

 

[Bondo]

Re: Spare prop negative effects??

I have a 16' Boston Whaler, Dauntless with a Merc 2-Stroke 115. We recently put an entirely new lower unit on the motor due to corrosion. Our primary prop is currently being shipped to us, the mechanic put our spare prop on for use in the mean time. I've run the boat briefly and have experience some odd effects:

With the engine trimmed all the way in, the boat rides high with the bow way up. The engine is rpm'ing way too high at cruising speed. I'm hoping these will be cured with the installation of our regular prop (which I think is a bigger pitch).

Is there anything else that could be causing this? And is there ANY way the wrong sized lower unit might have been installed, is that even possible?

Ayuh,.... Welcome Aboard,... What prop is the primary, 'n how different is the backup,..??

Without some sizes, there ain't no answers...

 

[steelespike]

Re: Spare prop negative effects??

As Bondo said it's difficult to tell much without some prop sizes.
But yes a prop could make the difference.Its unlikely the lower unit is the culprit.
Was the lower unit new or a used replacement?