Prop and a few other things

[jlasinski]

Just got a SR2300 with only 340 hours. It's in great condition and runs well. We did not get any manuals so here goes.

It has a 5.7 Mercruiser engine. How can I find out what the horsepower is? Not listed on the engine anywhere.

It has a 4 blade 14 X 20 prop and runs top end of around 44-45 m.p.h. Is this the best prop for it? Would a 3-blade or High 5 be better? If so what size and pitch?

Also, when running it for the first time yesterday the depth alarm kept going off at various times. I flipped the switch labeled depth alarm but didn't seem to matter. Any input there?

Thanks, John

[Phillbo]

As far as the prop goes.. It depends on what your WOT RPM's are currently.

[jlasinski]

I want to say it was around 45000 rpm

[mmwjr]

Originally Posted by jlasinski

I want to say it was around 45000 rpm

I think you have an extra 0 there. 4500 rpm would be near perfect set up for your engine.

[jparsons121]

Newer 5.7’s are 250hp for std and 260hp for the EFI.

4500 rpm says your prop’d right in the sweet spot

Depth alarm could be the shallow water alarm. What depth were you in when it sounded?

[jlasinski]

Thanks for the prop advice. Is a 4 blade prop better or is a 3 or 5 blade? Specifically are the High 5 any better? I was told I have a throttle Body efi on my engine. Is that 250 hp or 260 hp? On the depth alarm I think it was around 10 feet. Thanks

[jparsons121]

Propping is a compromise. There isn’t one “best” configuration. Each has its own strengths. As an example, The 4 blade adds bite, which typically allows for a better hole shot and provides a bit of stern lift, but there is more rotating mass and friction, so top speed compared to a 3 blade will be less. 3 blades are very efficient at speed, but have higher slippage coming out of the hole. High 5 is another hybrid, mixing more smaller blades with smaller pitch/diameter to have grip like the 4blade, and some efficiencies of the 3 blade.
It’s for smaller sterndrive or outboard boats.
If your happy with the performance with your setup, I’d stick with what you have. If not, be sure to know what you want to make better, because other things will be traded off.

EFI should be 260.

If you have the in dash sounder by Standard, pressing the top of the Alarm rocker switch should turn the alarms off another push turns them on. Settings for the alarms are done by pressing and holding for more than 3 sec.

https://manualzz.com/doc/22948514/st...d-owner-manual

[Phillbo]

How are you using the boat?

[jlasinski]

Boat will mostly be used for cruising. Kids like to tube but currently are not into skiing, but who knows. Is anybody familiar with Turning Point props which are supposed to have 2 geometry for better out of hole and better top end? They offer a 14 X 19 and a 14 X 21. Both 4 blade. Mine is 14 X 20 4 blade so not sure which way to go if I try it, up or down?

As far as the depth alarm, my switch is a toggle, up or down. Didn't seem to matter which way I flipped it, it still sounded.