2006 Opti RPM too Low?

[itsmeagain5789]

I tested out my 2006 Optimax for the first time yesterday, and its running at 5100 rpm. Max RPM is 5750.. am I too low, or is it normal to be lower than max RPM?

 

[hamit59]

Re: 2006 Opti RPM too Low?

Well from you post it sounds like the opti is running ok ? At all speeds ?
What model opti do you have ?
What prop are you running ( pitch , diameter)and on what boat? First off
max wot means there is a range that you should be in. On a 200hp you may be able to run a prop pitch @ 23"-25" on a 19 footer but you would never be able to pull the prop with a 90 hp on a 18 footer there's just not enough hp to pull it.
As for max rpm 75hp -115 the range is 5000 -5750 , 135 hp is 5000-5800
150-175 hp is 5250-5750 200 -225 hp 5000-5750 and 250 is 5500-6000
and all the pro xs wot is 5500-6000 175-250 hp As it shows you are a bit low
and you can drop your pitch down 2 " and get your wot up about 250 to 300 rpms but you will loose some top in speed but you will gain in your hole shot.
propping a boat is trail and error. What works best on one boat will not work all that well on another.
You can look in the prop form and get some ideas about what prop you should be running, but it all goes back to, What boat how much does it weigh and How much work it's having to do. Your prop will let you get all you can get out of the opti, But it will not make any more hp than you have.

I hope this helps you to understand wot range. I must say it took me some time and money in buying props and them not working on my boat to understand what I know now .

just my 2 cents worth or maybe 25 cents lol

hamit

 

[itsmeagain5789]

Re: 2006 Opti RPM too Low?

its a 200, and i put it on my 22 walkaround. it came off a 22 center console, but my walkaround probably weighs a little more.

 

[j_martin]

Re: 2006 Opti RPM too Low?

I disagree a little bit with hamit. If you're running considerably below the top end of the WOT rpm range at WOT, you're also not developing full power from the engine and thus not attaining top speed. Lower pitch will, in your case, increase both your top speed and improve your hole shot.

Other factors come into play for top performance. Engine height effects everything at the same time, for instance. Raising the engine may improve your hole shot, top speed, top RPM, and even handling. A little too high, and everything goes to pot. Also depends on the water you run in, and how much your load varies. In other words, the prop is only one factor in the equation for boat performance.

hope it helps
John

 

[jerryjerry05]

Re: 2006 Opti RPM too Low?

The FIRST thing to do is a compression and spark test.An engine that size can run on 5 cyl and you might not notice it unless you are looking for that.
Then consider the prop change.If you have a 21 then go down to a 19 or 17.
Tell us what you have on the boat now. Jerry

 

[hamit59]

Re: 2006 Opti RPM too Low?

John,
I agree with the motor height. I was thinking the proper set has been done.
I also ask some questions about the motor it's self. as Jerry had said if it's running on five it would not show if your not looking for it. this too will also cause a low wot. I would start to check out the motor as a whole compression spark and fuel, set up.
Hamit

 

[ufm82]

Re: 2006 Opti RPM too Low?

The walkaround is going to weigh considerably more than the CC. That alone will kill some RPM as the boat is simply harder to push than the CC was. Check the pitch on the prop that is on the engine and drop a size- I.E. if it's a 19 pitch go to a 17. Each drop in size should gain you about 400 RPM. (1" pitch= 200 RPM)
You may also want to look at the model of the prop. Bigger heavier boats like different style props than do lighter boats. A Mirage works better for big boats than does a Trophy. Props can be a real pain to dial in but are very easy to swap around to find what works.

UFM82