maxum 1900 XR with 150 optimax - Maxum Boat Owners Club

robbie83 · 07-10-2011, 09:41 AM

Hello everybody !
I FINALLY found a optimax 150 for my maxum 1900 XR '92.
It has at the moment a vengeance propellor 19 Pitch.
My top speed is 50Mph, or 80 Km/h.

In my opinion it is pretty slow for this combination...
Today i will see how much RPM it is going at full open throttle, but i thought it was around 5300.
I can trim the engine pretty high up, but it won't do that much to the boat...
Yes it does something, also to the speed, but it feels like it has to do a bit more.

My question is, do i have to find it in the type of prop or what else ?

I was looking for a laser 2 prop or ( i think is better ) the tempest prop.

Hope someone can help me with this.
Greetz from a sunny holland

Mag535 · 07-27-2011, 10:52 AM

RE: maxum 1900 XR with 150 optimax.
I got a 1997 150 HP 2 stroke on same boat from 1997. does a little bit more but is overeving (!) with a 15 x 21P mercury prop. Have you now checked your revs now and tested some new prop`s? I am looking at getting my revs down by 2-300 rpm and top7cruising speed up. Mag

robbie83 · 07-27-2011, 04:24 PM

Quote:

Originally Posted by Mag535

RE: maxum 1900 XR with 150 optimax.
I got a 1997 150 HP 2 stroke on same boat from 1997. does a little bit more but is overeving (!) with a 15 x 21P mercury prop. Have you now checked your revs now and tested some new prop`s? I am looking at getting my revs down by 2-300 rpm and top7cruising speed up. Mag

My revs are 5350 with a vengeance 19P prop on it.
I've not yet tested any other propellor, the weather is really bad in holland for 4 weeks... and still...

But i will try a 19P laser 2 prop, see what will happen.

I'm boating in fresh water, not in salt water... maybe that's why there is a difference in prop's ???
And my top speed is 80Km/h.

shrew · 07-27-2011, 04:45 PM

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[TR="bgcolor: #ffffcc"]
[TD]Manufacturer [/TD]
[TD]Model [/TD]
[TD]Horsepower [/TD]
[TD]Max RPM/Range
(Limiter) [/TD]
[TD]Gear Ratio [/TD]
[/TR]
[TR]
[TD]Mercury [/TD]
[TD]Optimax 2.5L [/TD]
[TD]150 [/TD]
[TD]5000-5600 [/TD]
[TD]1.87/1 [/TD]
[/TR]
[TR]
[TD] [/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD] [/TD]
[/TR]
[/TABLE]

shrew · 07-27-2011, 04:52 PM

I think you're approaching a paradox here. Going down in pitch will increase the RPM's, however it will lower top speed. Going UP in pitch will decrease RPM's and increase speed. However, you're going to begin hitting the 'law of diminishing returns' very shortly. How much more pitch do you increase before you're straining your engine in an attempt to eek a few MPH/KPH out of the motor.

You won't be running around all day at WOT. At some point you're going to need to be satisfied with teh boat or buy a boat made to run at high speeds (e.g. Fountain, Cigarette, etc).

robbie83 · 07-27-2011, 05:50 PM

My optimax is from 2003.
the max rev is 6000.

I will first try a laser 2 or (if i can find one) a tempest !

The boat at full speed claps on the water with normal waves, that is not so nice about this boat...
It really hurts your back, and the clap it makes can't be good for boat / engine / me.
Is that normal with maxum?

thanks guys so far

Mag535 · 07-27-2011, 08:01 PM

How do you know that you get 6000rpm? If so, then you are overevning badly. My boat is going steady as a rock at all speeds when trimmed right. My 150 hp V6 is a 2 liter engine. Can it be lighter than the Optimax? It would be nice to know the weight.I will propably go with a solas 14 1/4 x 22P 3 blade ss prop instead of the 15 x 21p alu I got now.

I really love the boat and the performance. I was just out in the archipelago again in Finland this evening. 23 deg C in the water and the 4th week with over 25deg c in the air. It is just super.

Mag

robbie83 · 07-27-2011, 08:54 PM

He Mag, tonight i was on the water

I think aluminium you can have a higher pitch then a RVS prop !!! so ask for that before ordering...
A solas is not a good prop... it is only a rvs prop and that's it !
If you want high performance you will go to a good brand or type of prop.
Nice to know that you are from finland !

ooh and by the way, i also had a 150 v6 2.0liter engine on it and the top was about the same (78km/h) with an aluminium 21p prop...
greetings and sleep well,
Robert

Mag535 · 07-28-2011, 12:16 PM

Hi Robbie83

Why do you say Solas is no good? It is today the producer of most OEM props also. Even though it is made in Taiwan it does not have to be crap.
Why did you change engine?
Mag

robbie83 · 07-28-2011, 05:26 PM

nobody talks about a solas...
probably because its a standard thing, and that is not what people want !
People who wants to buy a prop, wants performance...
I know solas is ok, but not if you want the best out of it.

I changed my engine because i was looking over a year for a optimax, and could not find one, until i bought a 2.0 mariner.. so that's the story.
Optimax is a great engine and is VERY VERY fast in accelerating !!!

shrew · 07-28-2011, 08:13 PM

Quote:

Originally Posted by robbie83

My optimax is from 2003.
the max rev is 6000.

Actually according to the specs for the 2003 Optimax 150, both the Optimax and the Optimax Saltwater had a Max. RPM Range of 5,000 - 5,600 RPM's. If you were getting 6,000 RPM's then you were underpropped and over revving the motor. On the other hand, your tach could have been out of calibration.

robbie83 · 07-28-2011, 08:32 PM

you're right !!!
i'm sorry, i thaught it was 6000, but mine is a saltwater 2003 optimax and max RPM is 5750 !!!
That's what it says on the sticker on the engine.

Mag535 · 07-29-2011, 08:24 PM

My local service guy had an used alu 13 1/2 x 23P prop that I could test my 1900Xr/150 hp V6 with. My std prop is a 14,25 x 21p prop. What a disapointment. With my std I do 53mph and close to 6000rpm. With this it did barely 46mph and 5400 and it was almost impossible to trim and get to go straight at full speed. I am trying to find the right setup to get a spare prop and rpm down to 5600 and I will propably now go for the same I got but as SS. Any comments?

Mag

robbie83 · 10-31-2011, 09:11 AM

so, my RPM is : 5350 with the trim @ 8 - 9 ! and the topspeed is 80km/h or 50mph
the prop is a 19p vengeance
The boat will not lift easy, so i have to trim it a LOT, otherwise the speed is also lower...
so i am pretty shure that i have to raise the engine 1 hole more up, or maybe 2 holes !!!
I will post a picture of my engine how high it is hanging at the moment...