Minnesota Classic Glastron Forum

General Category => General Discussion => Topic started by: dszczucinski on May 16, 2018, 01:34:16 PM

Title: Glastron Carlson Propeller Size and Type
Post by: dszczucinski on May 16, 2018, 01:34:16 PM
Hey all,

I am looking to finally replace the propeller on my C512 Metric with the Mercruiser 120 engine and outdrive. Just wanted to see what prop everyone was running as my replacement is well overdue.
Title: Re: Glastron Carlson Propeller Size and Type
Post by: 75starflight on May 16, 2018, 02:37:33 PM
I am currently running a laser II 21p on my v179. My v179 is a 17' tri-hull with a mercruiser 140. I also ran this same prop with a mercruiser 120 in the same boat. The laser II is for speed, for pulling I use an aluminum 19p prop.
Title: Re: Glastron Carlson Propeller Size and Type
Post by: nes-cv23 on May 16, 2018, 06:05:47 PM
This is the prop I’ve had on all my boats from the 16 ss with a 120 all the way up to my 23 with the 350 that’s been tweeked a little. It has been the beast all around prop for me, good speed on the little boats and nice power on the big ones.  it’s a 19p ss and I wish I had another..
Title: Re: Glastron Carlson Propeller Size and Type
Post by: C512Jim on May 17, 2018, 06:10:46 AM
What do you mean by tweaked?  I tried a 21p mirage prop one time and it really worked that little 120hp to get out of the hole.  The photos show the prop that came with the boat when I got it and he must have had it figured out what was ideal because has done great out of the hole and at top end with a load in the boat.  If you search "Glastron Carlson C512" on youtube you will see what that prop does on the boat you are asking about, especially with two big guys. lol.
Title: Re: Glastron Carlson Propeller Size and Type
Post by: Hyperacme on May 17, 2018, 06:55:56 AM
Your 17P looks like a OMC prop, with the divergence hub thingy (the flare on the back).
Try a Laser II prop, maybe 19P to start with, pick them up on local Craigslist for $200 to $250.
Try to find one with the "Flo torq" hub, which would be the newer style / model of prop.
Merc also makes a Quicksilver brand prop that isn't as highly polished as the fancy Laser II, but is about same prop.

The best method to finding the right prop is testing as many as possible.
#1 ...Make sure your RPM's are in there upper range of rated "Max. RPM's"
#2 ... Feel , Is the prop getting out of the hole, not blowing out in turns or fast take off, etc.
#3 ... Unless you test a bunch of props all on the same day, speed will very by 2 to 4 MPH, so hard to say Max. speed from day to day, with different water conditions , hot / cold temps, etc.

Tweaked ... A prop shop can bend blades to increase pitch or cup blades for more bite, change a stock prop to better fit your boat and boating needs.     It "Black magic" stuff ... LOL

My 2 cents ...
Merc props work well on Merc motors.
OMC prop work well on OMC motors.
 
Title: Re: Glastron Carlson Propeller Size and Type
Post by: Jason on May 17, 2018, 10:16:59 AM
I agree, try a Laser II. They work well on these light weight Carlson's. I run a 23p Laser II on my CV16SS with a 140. I tried a bunch of different props and the 23p Laser II performed the best and has been a common story for the 16'-18' Calsron I/O's. With a 120 I bet a 19-21 will give you the numbers you are looking for. If you are still not getting at least 40-42 at around 4500 rpm then you have something going on with the motor or boat.
Title: Re: Glastron Carlson Propeller Size and Type
Post by: 75starflight on May 17, 2018, 12:23:17 PM
Just from experience. When I switched from a 19p aluminum prop to a19p stainless prop I saw a gain of a a couple MPH when I was running my 120.

yes Stainless is more expensive, but it reduces flex in the prop when under load.
Title: Re: Glastron Carlson Propeller Size and Type
Post by: dszczucinski on May 18, 2018, 09:28:45 AM
Hey all,

Thank you for the recommendations. The local shop here in town is quite friendly and allows you to test different propellers until you dial it in. That said, our original propeller was a 14.5 x 19p three blade. I purchased a new one (Mercury Quicksilver brand) in the same size ($125). Off the bat I would say mph and drive-ability/holeshot improved.  But, we are really maxing out at around 35mph at around 4200 rpm. For a 120, would you consider this to be normal? Should we go for a 21p or a 4 blade 18p? I just don't want to lose the holeshot speed as we really use this boat for skiing. 
Title: Re: Glastron Carlson Propeller Size and Type
Post by: Plugcheck on May 18, 2018, 10:15:52 AM
RPM's,(4200) seem low with a 19p prop.  I wouldn't go higher in pitch since it sounds like it might be struggling with the 19.  Couldn't hurt to try an 18 or even 17.  Not sure your mechanical abilities, but you could check compression and valve train.  Quite possibly the 120 may be getting a bit tired?  In the end, if it works for what you do most, sounds like skiing, then I'd use her this season, and maybe refresh over winter.  Could be other things as well, hull finish(barnacles?)   Or maybe developed a hook on the trailer?
Title: Re: Glastron Carlson Propeller Size and Type
Post by: Hyperacme on May 18, 2018, 10:45:30 AM
According to info I found ...

1981 120 Mercruiser max rpm's = 3900 / 4300 ... 1981 140 Mercruiser max rpm's 4200 / 4600 ..

If your local dealer will let you try other props ... DO IT !
You never know how well it will preform .. Until you try a prop ...

1980 / 1981 C-512's only motor was a 140 OMC or Merc ... But you both have 120 HP Merc. in your C512's ?
Brochure's are wrong on a lot of stuff ...

It's a good idea to carry a spare prop, like a spare tire on your car. So get one for pulling ski/tubes and one for speed .

It could be you have water in your hull and wet saturated foam ?
Speed seem kind of low for your RPM's.

Title: Re: Glastron Carlson Propeller Size and Type
Post by: C512Jim on May 18, 2018, 11:18:48 AM
Great information Gregg.  We Just got my sons shorestation put back together and in the water, got done at 10pm last night (started at 7 30 pm. lol).  Hope within a week, maybe even this sunday his C512 will be enjoying its new home on West Grand Traverse Bay on Old Mission Penninsula.  I am currious why the 120 and 140s have different rpm ranges when its pushing the same boat and guessing basically the same engine?  Full throttle with that 17p is running at 4500 rpms, I almost alway back off to about 3/4 since you only loose a couple miles and hour.  Will check my 82 to see what props it has on it, came with two stainless.

That was the view looking out on Power Island last night just before we rolled out the lift to the right side of the docks.
Title: Re: Glastron Carlson Propeller Size and Type
Post by: dszczucinski on May 18, 2018, 01:00:56 PM
Thanks all!

She is an old boat so it may just be struggling a bit :-) Based on your great info we appear to be right at the max RPM we should be at.
Title: Re: Glastron Carlson Propeller Size and Type
Post by: 75starflight on May 18, 2018, 01:09:03 PM
  I am currious why the 120 and 140s have different rpm ranges when its pushing the same boat and guessing basically the same engine?

To answer this question the 140 has a longer stroke crankshaft while the 120 is a shorter stroke. They are essentially the same block, head, ect. The difference is in the stroke.
Title: Re: Glastron Carlson Propeller Size and Type
Post by: Diamond Chad on May 18, 2018, 01:25:14 PM
Nice Picture.  I'm just sayin.
(http://employees.casinotrac.com/CarlsonRed2.jpg)
Title: Re: Glastron Carlson Propeller Size and Type
Post by: C512Jim on May 18, 2018, 02:37:02 PM
great input on the difference of the stroke, makes sense on the rpm then.  Locally there is a guy that used to build the iron dukes for drag racing, wonder what you could actually get out of them safely.  But have to say stock they have always been a great dependable motor that is very inexpensive to run, for me anyways. Very nice Glastron enhanced sunset photos by the way.
Title: Re: Glastron Carlson Propeller Size and Type
Post by: C512Jim on May 18, 2018, 03:05:15 PM
I did check out the metalic metric I picked up a few months ago and looks like you were right on the money with your suggestions and the previous owner of my boat agreed. lol.  You got me on the spare prop that was in the boat, need to figure that one out and what they were doing with that.
Title: Re: Glastron Carlson Propeller Size and Type
Post by: Hyperacme on May 18, 2018, 06:42:22 PM
 The one on the drive is definitely a Merc prop .
 Probably a quicksilver 21 pitch .
 Can’t remember the name of the prop with squared off blades
 Somebody will chime in with what it is
 Popular prop though , I didn’t have much luck with it on my boat
 Not to say that it couldn’t work great on your boat
Title: Re: Glastron Carlson Propeller Size and Type
Post by: 75starflight on May 18, 2018, 07:01:47 PM
The first prop says laser II in the first pic. That second is a ballistic.
Title: Re: Glastron Carlson Propeller Size and Type
Post by: C512Jim on May 18, 2018, 07:30:54 PM
is the ballistic prop actually made with the ears bobbed like that?  it actually feels lighter and the blades are thinner than others I have.  May let my son try the laser II out on his boat this summer, will have the other one tipped and cleaned up and see what it is, cant quite read it out on the inside of the hub anymore.
Title: Re: Glastron Carlson Propeller Size and Type
Post by: Hyperacme on May 18, 2018, 09:11:05 PM
OK ...
Was looking on my phone ...
Clearly see it on my lap top ...
Laser II 21P & Ballistic

Square hole's on Laser II would make it older style, with out Flo Torq hub.
Good prop ! 

Ballistic's were designed that way.
Were is Dave P. when ya need him (AKA  The Prop Hunter)