prop question

[75starflight]

Looking over the out drive today and found mfg markings on the prop. I know absolutely nothing about props , so here is the info.

Vortex mi wheel
992004  14.5 x 19

Just wanting to know a little more about it, I presume it is the stock prop for a mercruiser 120. I just really want to know what kind of performance to expect out of it.

[Hyperacme]

It's a 19 pitch aluminum prop from Michigan Wheel Marine  .
Do you have a tach ?
Do you know  your motors max. rpm's ?
Only way to tell is take it out and run her, check rpm's to see if your over revin' or not gettin' enough R's.
Then go up or down in pitch to get motor into that range.

http://www.miwheel.com/propellers/outboard/vortex/

[Rich_V174SS]

Knowing what your maximum rpm is at full throttle will be the only way to tell if your prop is an efficient choice for your boat/engine combination. You want your engine to max around 4500 rpm +/- 100 rpm.

When I had a Mercruiser 120 in my V174 I was running a Mercury aluminum 21 pitch prop and getting 36 mph @ 4600 rpm. Switching to a Mercury 21p stainless steel prop gave me 39-40 mph at the same 4600 rpm. Going up in pitch one size will lower engine rpm by about 200. Conversely lowering the pitch one size will increase rpm.

[75starflight]

Well if my memory is correct I never did push the 120 to WOT last year while not pulling a tube. But during its first run under my ownership I did get 30mph at around 3000rpm that is if the old tach was reading right.  It always showed 1500 rpm at idle, but after removing I from the boat I think it was a ground issue. I guess when I do my shake down run in may I will find out what it can truely do. Thanks for the info.