Good enough RPM or not (92' Yamaha 130 v4 2 stroke)

Hello all,
Just picked up a new to me boat thought I'd toss some information out there and see if anyone had any recommendations or just stick with what I have. I'm interested if the current RPM I'm hitting is "good enough" or if I should change props to squeak out a little more RPM (closer to 5500). The rating for the engine is 5k-6k. Just wanting to prioritize engine health. Of note is I'm not a speed demon; I like torque and hole shot much more than speed.
1) Performance issue you are trying to correct.
- Engine RPM at WOT.
2) Current prop manufacturer, model, aluminum or stainless as a minimum.
- Yamaha 21-K, aluminum
3) Current prop diameter and pitch (required).
- 12-5/8 , 21in pitch
4) Wide open throttle RPM and speed with an average load (very helpful)
-5000-5200, 45 mph(gps), seen 5400 one time (47mph), takes a while to hit 5000-5200.
5) Engine/drive make, model, year, and HP
- 1992 Yamaha 130 v4 2 stroke outboard.
6) Boat make model, year, length and weight
- 1992 Ebbtide dyna-trak 178 ss, 18ft, weight 1800~ estimated.

1992 fast runabout running great.
You want to start changing parts ?

Just trying to make sure I was running the proper RPMs for engine health. I grew up with tiller 25's with no gauges and those are the only boats I've had till this.

Sounds like you might be a little heavy on the pitch but not that much, however, you have to decide if it is worth the effort and cost.. In my 60 plus years of boating, I have always propped my engines to reach max wot with the lightest load....just me and necessary eguipment. If you have extra weight or use pull toys a spare prop with less pitch might be needed for that hole shot. All depends in what you do with your boat and how much weight you carry. If it were me....I would adjust pitch to reach 5800/6000 rpm at wot with just you on board with necessary gear then carry a spare prop with slightly less pitch in case a heavy load or playtime requires it. However, your money, so what all are you gonna do with your boat ?

airshot said:

Sounds like you might be a little heavy on the pitch but not that much, however, you have to decide if it is worth the effort and cost.. In my 60 plus years of boating, I have always propped my engines to reach max wot with the lightest load....just me and necessary eguipment. If you have extra weight or use pull toys a spare prop with less pitch might be needed for that hole shot. All depends in what you do with your boat and how much weight you carry. If it were me....I would adjust pitch to reach 5800/6000 rpm at wot with just you on board with necessary gear then carry a spare prop with slightly less pitch in case a heavy load or playtime requires it. However, your money, so what all are you gonna do with your boat ?

Click to expand...

Don’t intend to pull any tubes or anything like that any time soon. Mostly to hit the fishing spots, and joyride with the wife and child occasionally. I think reproping for the 5.8-6k with just me for primarily fishing, would be ideal.

If the WOT Range is 5000-6000, then you should be propping it to get close to 6000. You will likely find several props that will provide that, but they may should differences in how the Boat Rides, Handles, and what the Top Speed is.

Looking at the Trailer. I wonder if that had Initially been a Roller Trailer. It looks like an EZLoader. The Front Crossmember is Pivoting, even though it is Attached to a Bunk

jimmbo said:

If the WOT Range is 5000-6000, then you should be propping it to get close to 6000. You will likely find several props that will provide that, but they may should differences in how the Boat Rides, Handles, and what the Top Speed is.

Looking at the Trailer. I wonder if that had Initially been a Roller Trailer. It looks like an EZLoader. The Front Crossmember is Pivoting, even though it is Attached to a Bunk

Click to expand...

Yeah my cousin saw it in the picture and noticed something different about the trailer as well. Do you have a recommendation on a prop size you would try if it were you?

Every inch in n pitch changes engine rpm by 200 rpm, every inch in diameter changes rpm by 100 rpm. Those are the general rules of thumb. Use your current prop at wot, and adjust accordingly.