2014 Mercury Optimax PRO XS on 24Ft. Manitou Tritoon, RPM issues.

[trout74]

Facts:
24ft. Manitou Tritoon VP hull
150 HP Mercury Optimax PRO XS ( 2014)
Mirage Plus 15P Prop.
5.5 Hours on the Motor

Situation:
I have carefully watched RPM's and ran it from 2800 -4500 RPM's with short bursts of WOT. Also pulled kids on tube in that RPM range.

Max RPM's I can get is 5000 RPM's and that is playing with the trim with just me and Wife and no gear on board.
With me and the Wife and my 4 kids ( ages 2-10 ) my Max RPMs today was 4750RPM's. Full cooler, gear etc. Remember these kids are little, biggest one weighs 90 pds, and the rest are squirts still.

I called Mercury and they verified to me that the computer logs time spent between 2800 and 4500 RPM's and double oils for 120 minutes that the motor is in those RPM ranges. Any idling and WOT, it does not double oil and does not go towards the 120 minutes. Once the 120 minutes is up, the engine should gain 300 RPM's or more and stop the double oiling. He said it will be like a light switch once the 120 minutes is surpassed.

I have been very careful to be running in the RPM range of 2800-4500. The engine timer shows 5.5 hours after 2 hours of engine time on the water today with the family. I find it inconceivable that I haven't passed the 120 minute mark yet. Yet I haven't had the " light switch " moment yet.

Shouldn't a 150 HP Optimax be able to spin a 15P on a 24 ft. boat?
I know I could go to a 13P but that theoretically would only take me to 5300RPM with just me on the boat, so then going by the math you would go to an 11P for 5600 RPM's, and that seems too low for a 150HP on a pontoon boat.

Its possible I'm still in the computer controlled break-in, but I don't know how I could be.

Any thoughts by anyone here?

Thanks for reading long post,

Graham

 

[Texasmark]

Can't fight the computer. However on conventional carbureted engines in the days before all the high end electronics, prop sizing is determined on the boat with the load you carry most frequently, taking the necessary corrective action at other times.

If you run light most of the time, get out on relatively calm water and max out your rpms paying attention to trim position settings. The recommended rpms at that time should be at the upper limit of the recommended range or thereabouts. The few times you have a big load should still have the rpms in the recommended range at WOT. If not, lighten the load or decrease the pitch,.

If you run heavy then the same thing applies. However you need to keep your throttle in check to keep from overreving at WOT with a light load.

I don't know how much oil the computer decides to dump into the fuel but I would think that it would take a good bit to really impact the rpms.

But as I said, I don't know.

Mark

 

[Chris1956]

I am with Mark on that. Double oil shouldn't affect RPM at all. Not sure why dealer made that statement.

On the other hand, is it possible the computer limits max RPM? That would sure make sense during the break-in period. I would think you need to wait for the motor to come out of the break-in period and see what your max RPMs are. 'toons are not real high performance, so I would not expect too much speed. Heck, a 150HP on a 24' cruiser would be a bit of a dog.

 

[dan02gt]

Why did the dealership put a Mirage on it instead of an Enertia? The Mirage is for high horsepower stern drive sport boats and the Enertia is Mercury's high performance pontoon prop.

People do state there is a performance difference when the motor comes out of breakin mode, but it's not that drastic. Most people claim a MPH or 2 on a bass boat.

 

[trout74]

its a mirage plus, does that make it more appropriate? would an enertia give it more RPM's?? at the same pitch?

 

[The Rooster]

Graham, my current barge is running an Apollo prop, but the previous 2 barges were set up w/ Enertia props. All SS 3-bladed.

 

[trout74]

so do you think that the Mirage plus is not the correct prop? would a enertia 15P really change RPM's over a mirage 15P. I dropped boat off at dealer yesterday, and he said he would have it ready in a week. He did have a ton of boats ahead of me. As long as I get 5700 RPM's with a light load I don't care what prop it is, unless one is appreciably better than the other. The waiting game now, I hate waiting.

 

[dan02gt]

The Mirage plus isn't much different the older Mirage. I think the PVS holes and hub are the only differences. Think you will get more speed and RPMs out of the Enertia do to it being a better design for your boat but the only real way to tell is to run it.

 

[jestor68]

The Mirage is the wrong prop design for a tri toon. That is intended for higher HP (225+) motors.

The Enertia is the prop Mercury recommends for tri toon boats. It is a full inch smaller in diameter compared to the Mirage, in addition to being a different design.

Your motor will turn the same pitch Enertia at a higher rpm; as much as 300-400 rpm higher.

 

[The Rooster]

I'm currently running an Apollo prop Graham, but my last 2 barges w/ Optimax's had Enertia's. Great prop.

 

[trout74]

Ok, I'll tell dealer to put an Enertia on it. Thanks guys! Hey rooster, why the Apollo, is it better yet?