maxum 1900 XR with 150 optimax

[robbie83]

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]

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]

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]

Manufacturer	Model	Horsepower	Max RPM/Range (Limiter)	Gear Ratio
Mercury	Optimax 2.5L	150	5000-5600	1.87/1

[shrew]

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]

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]

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]

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]

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]

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 !!!