What size and pitch prop are you guys using on your mercs 150hp?

[cbucner]

Finally got my boat out today and she runs like a dream.
One issue is water pressure low , I could not get over 8psi at wot , I'll have to look into that, but my problem was that the boat when it takes off the bow gets pretty high and it takes a while to plane.
I have a stainless Trophy II 3 blade 23 pitch, I didn't meeasure the diameter yet but just curios what are you guys running?
I forgot to mention my WOT was 5000 max so it looks like the 23 pitch it a little too much .
Any sugestions will help.
Thanks

 

[israelbass]

Re: What size and pitch prop are you guys using on your mercs 150hp?

if you have a jack plate try droping your motor a littlle 1".if you still have water press. prob. new pump kit and check poppet valve and thermostats i would not run engine at wot under 10- 15 psi. water press. check engine serial num. plate for max. rpm. i think yours is around 5600-5800rpm. does your prop have any air vent holes on hub?if not have a prop shop put some in and re-cup blades should be fine

 

[cbucner]

Re: What size and pitch prop are you guys using on your mercs 150hp?

Took her out today again.
Changed the prop to a 4 blade 14x21pitch from my other boat.
Installed a water temp gauge .
So this is the story, I can hit now 5600-5800 rpms at WOT, water pressure after a couple of runs went to about 16psi at wot and temp at WOT or around the 5000rpms stays around the 145-160MAX.
At idle pressure is almost 0 temp goes out to about 170-190.
little better hole shot with the other prop but still bow kinda gets high on take off, i have to hammer it to get on plane fast and level.
So what still worries me is pressure at idle and temp at idle.
Thanks for any inputs.
I will go to a 14x21 4 blade just to keep the rpms to 5600max and gain few mph at top end.

 

[steelespike]

Re: What size and pitch prop are you guys using on your mercs 150hp?

As far as your performance we could tell better where your at if we knew what boat (light and fast?) max speed and rpm.
If you don't know the age/condition of the impeller you should change it.
and check israelbas's suggestions.

 

[Benny1963]

Re: What size and pitch prop are you guys using on your mercs 150hp?

also sounds like you are haveing pump issues or your jacked to high.
id clear up the temp and pressure probs before ya tear up ya mota
good luck bennyb

 

[Benny1963]

Re: What size and pitch prop are you guys using on your mercs 150hp?

also sounds like you are haveing pump issues or your jacked to high.
id clear up the temp and pressure probs before ya tear up ya mota
good luck bennyb

 

[cbucner]

Re: What size and pitch prop are you guys using on your mercs 150hp?

Boat is a 1994 Nitro 190DC.
A 19ft bass boat.
From what I remember the guy who owned it before run it in some murky waters and I noticed when I ran it into a barrel at home that I found lots of sand and small gravel at the bottom after i drained the water, and the increase in pressure the more I run it looks like needed to be run to flush out.
What I will do , I will remove the stats and run it that way just to flush it out.
Then I will install the stats and see how it goes from there.
The impeller and housing are new , stats are new .
I started wih about 6 psi of pressure at wot and now I'm at about 16psi so it looks like is flushing out.
Still what I don't like is the bow that gets way too high on take off.
trim all the way down and boat get's to about 45deg on takeoff.
I'm used to my other boat , I have a sea ray 180 with the I/O and that one goes just a little up on takeoff.
On the Nitro I have 3 batteries , full tank of gas 35gal's , so I don't know.
If I have somebody up front it's better .
I'm trying to figure out if this is normal or something needs adjustment.
Also when you slow down the water catches up with the boat and the wake goes over the motor 1/2 way, kinda scary the first time.
It looks like something is wrong but have to figure out what.
How can I tell if the motor is mounted too high or too low on the boat?
will a higher motor bring the bow down on takeoff?
Thanks

 

[cbucner]

Re: What size and pitch prop are you guys using on your mercs 150hp?

Just checked on the boat and I have 5 adjustment holes on the mounting braket of the motor.
It's mounted all the way down.
So after I get some suggestions regarding the hight of the motor I will maybe move the motor one hole up just to see how she goes.
Thanks for any inputs.
Where do you guys have your motor mounted on the bracket?

 

[cbucner]

Re: What size and pitch prop are you guys using on your mercs 150hp?

Also from what I read here on teh forums it looks like the teleflex probe reads kinds high so I will wire the original merc temp probe to the gauge to see wht that one reads.
the teleflex one goes to about 170 and starts to jump to the end of the gauge and one it's cooling under 170 it reads fine, so I don't know until I clear all these issues .
I checked with a ir temp and i was getting 145 running at idle , the teleflex sender reads over 170 .
What will be a max temp for this engine and what will be a good operating temp range, idle-wot?
Thanks