Minnesota Classic Glastron Forum
General Category => General Discussion => Topic started by: fireman24mn on August 20, 2012, 10:28:42 AM
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So after trying a few props this weekend. I am thinking that I need a 25p. I have a 21p merc prop and that goes 57 at about 5000rpm. I tried Jeffs 23p Lazer 58.5 but 5200rpm, tried Tims 24p last week and was at 58.0 and 4200 rpm then tried Jeffs 25p lazer and got 60.0 at 4700rpm. I also am going to look into the gear ratio in my outdrive and see what it is. Thinking I should be faster than I am.
Next would this fit my boat. I talked to him and he is confidant that it will but there is no model number on the prop just size and pitch.
http://minneapolis.craigslist.org/ank/boa/3200464371.html (http://minneapolis.craigslist.org/ank/boa/3200464371.html)
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You probably already know this, but just something to keep in mind as you compare to other props, that Lasers have a little less diameter and a little more slip than other "popular" props...which for some reason works really well in a lot of cases on most of our Carlson hulls. I don't have any experience with the Yamaha prop you referred to, so hopefully someone else can help you there with it's diameter and reputation - but if you start looking at and comparing/considering tempests and other popular Mercury props, you might want to reduce the pitch a hair, or your RPMs might fall much lower than you're shooting for.
Sounds like you're getting pretty close with the 25p Laser though. You might want to consider and test something like a Big Ear Chopper for that last final speed tweaking bow lift if top speed is the only goal? (just a thought) :)
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I am looking for both top speed and the kids need to tube and ski. Probably end up going one prop for speed and one for water sports
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I am looking for both top speed and the kids need to tube and ski. Probably end up going one prop for speed and one for water sports
I've kind of resigned myself to just running with the water sports prop all the time now...that's the only time we use the boat!
I suppose I could have one just for the meet weekends...
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For the tube and ski purposes, the High Five pulls like you wouldn't believe and I see good reviews most of the time, but on mine the steering torque on the wheel in high speed turns was quite surprising and you do give up some top end - but I have a CLE lower unit which has a longer nose cone, so a "fiver" might not give you that same problem - but might be worth considering trying/testing out if you're into serious tubing.
I don't mind changing props and I like to test...but I have an outboard that I can get at a little easier than if it was an outdrive too. It's surprising the difference between each prop design and how each hull responds differently. Technically, my big ear chopper does very well for speed running, but we decided to use a laser for this past event and I/we were very happy with it's performance - but as you pointed out, the events are fun for all out speed running for a lot of us rather than pulling. Nothing wrong with having a prop just for the "Event Weekend"! ;)
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I agree on the lasers. They do have some slip at take off but that doesn't bother me at all. Kind of makes it feel like your doing a burn out in the water!! I love my laser II 23p.
Keep in mind that pitch and diameter are not the only things affecting performance. The design/shape of the blades have a lot to do with it. That Yamaha looks very similar to a laser II. I have heard too that yamaha and mercury props interchange.
All you can do is keep trying different props.
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I thought I'd have to drop my pitch - even had a Quicksilver bronze 2-blade 15 pitch in the car. I got up to 5100 RPM this weekend - 300 better than I'd been able to reach before. There might be a little more room to get it to 5200+ ...
Needless to say, the bronze 15 will make a nice paper weight.
I'll stick with what's on there until I have an opportunity to try others ... I'd like to try a 2-blade. Maybe I can find one with a 19 inch pitch.
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I was running a 19P High Five last weekend on my CVX18 and that prop gives up almost 2 MPH on the top end versus the 19P SS 3 blade that I sold to Brandon. They're slow but as already said pull like a freight train when you need it to. And it is silky smooth. Still a CVX18 isn't short on power so any 3 blade with a lower pitch will probably give you satisfactory hole shot for most water sports.
Like Jason said keeping trying different props for top speed. I think for the CVX18 you just want something with a raked blade that helps pick the bow up.
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The Yamaha prop i listed above is a bigger diameter prop (14.5) then the lazer 2 think I will end up dropping down in RPMs too much? Or think maybe I should try to run a larger diameter 23 or 24.
Also what gear ratio came in the stock lower unit 188hp mercruiser 302 any ideas?
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Should be a 1.50:1, same as the GM V8s.
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Not sure why we didn't put my 23p turbo on your boat this weekend. You need to try it.
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Ya I will have to get it from ya and try it out.
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One thing about props is that almost everything any of us suggest is a "best guesstimate" until you try it on your specific setup. I've seen it referred to as a bit of a "black art" because almost no two setups are the same and sometimes even the same model props out of the box are a hair different. But with similar hull designs and motor combinations, an awful lot of the advice you'll receive here will be very close, if not exact (and probably a lot better than mine) from people who've been in your "same shoes" so to speak. :)
I've always thought that wouldn't it be a dream to own a prop shop and have the means to be able to stock almost all kinds of props just to try out and then still sell the ones that don't work on your own setup?
I didn't want to "muddy the waters" before, and I assume you probably know a lot of this already, but yes, there is not only diameter and pitch of a prop to consider, but leading and trailing edges, rake, over hub exhaust, through hub exhaust, over AND through exhaust, ventilation holes, variable pitch or shift on a few specialized props, etc, etc...and in a dizzying array of combinations, and then you have to consider lower unit height and angle, distance behind transom, exhaust route (through hub, through transom, or in my case above anti-cavitation unless I put plugs in). And I only know some of these things because I read and experiment a lot - some of you probably know "gobs" more about other details then I ever will.
Anyway, the point is not to get lost in the details, but part of the best "guesstimate" part is to assume certain design features such as on one hand Cleavers are transom lifters and generally made to run partially out of the water but do have a history of running fairly well on some of our Carlson type hulls, the other end of the spectrum is the Chopper which is a bow lifter for speed, the Laser II has a fair amount of rake for bow lifting but is a smaller diameter to allow a little slip (don't confuse this with it's ventilation holes, those are used to get the RPMs up on takeoff). Two blades you have to be careful of almost any blade damage causing damaging vibration on the lower unit's parts than what similar damage would to a three or more blade unit, all the way up to the five or more blades which have almost no vibration but start to "get in their own way" from top end and even reversing. I'm sure I've left out a lot of things trying to make this point, and even some of the "accepted rules" of the designs are broken when put on a different combination of hull and motor(s) (I've heard of a high five that not only had more pulling power like you'd expect, but actually was faster on the top end - which is definitely not the normal result).
So in the end, everything is a suggestion based on how the cupping-raking-diameter-leading/trailing edge-pitch-& number of blades combination (Laser, Trophy, Tempest, and numerous other models & brands) have worked on similar boats...but still expect it might work a little different than expected when tried on your specific setup.
Doesn't get much more fun than that - does it?? (aren't you glad I didn't muddy it even further by mentioning labbing where the prop is blueprinted and thinned for a little more speed and/or efficiency but sometimes leads to early failure just like some welded blades that reportedly crack and fly off eventually?) LOL ;)
So...just my suggestion for you for what it's worth - the ideal would be to get to know a local prop dealer if you can and/or friends like those on this forum who might even let you borrow some props...and then experiment A LOT with as many styles and sizes of props as you can get your hands on - if you want to that is. But I suspect that "CVX Fever" gave some of the best advice, which is that in the end (which I'm sure is why you asked the question in the first place - I know, I'm being "Captain Obvious") a 3 blade dialed in for speed will be your best bet when you want to go fast and get a smaller pitch 3 blade for your average watersports load. That's probably the best of both worlds and you'll be able to carry the other one as your backup prop. :)
PS, I've heard good things about the Turbo's like what "still_fishin" just suggested. Didn't work as well in my case when I tried one, but I have seen many good reports... :)
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" tried Jeffs 25p lazer and got 60.0 at 4700rpm "
YA ! The BIG 60 !
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Thanks Jim a lot of good info. There are so many variations it is ridiculousness. I will just keep trying them and see what I can find. Just sucks spending money on one then find out that it don't work any better than the last one. I will keep trying them and see what I can find. I am thinking 4 blade 24 or 25 would be nice to try, may be my best of both Take off with top end.
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Shawn
Supreme Marine will rent you a props to test ...
I have never done it, and not sure how it works, but give them a call ...
http://suprememarinemn.com/ (http://suprememarinemn.com/)
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Shawn
With the variations in your tach readings with the same prop only different pitch, maybe you could look at trying a different tach. Because as we talked the readings made no sense.
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I dunno but the $80 yammie prop looks like it could have some potential. Yeah probly a lil too tall as is, but if'n ya thinned the blades'n mebbe knocked a lil of the cup outa it I think it would rock. For top end that is. Blade design looks alot like a Lightspeed or Raker?
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I have never done it, and not sure how it works, but give them a call ...
I'd imagine it works kinda like when you 'rent' a tool from the car parts joint. Meaning you pay for it first & if you don't break it you should get your money back upon return. Evidently the buy it if you break it policy wasn't paying off? Too bad.
I miss the good ole days when my buddy ran the parts department at Jafco marina in Buffalo. Had a plethora of props at my fingertips. Imo with an IO your only option is to monkey around with the prop. Trim tabs mebbe.
We discovered that for top end my Formula F206 w/233 Merc (351ci) liked a big diameter wheel. Naturally it was useless for anything else but once it finally climbed outa the hole'n got on plane it felt like a windmill was pushing you.
edit: I was a much younger man back then ...
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So I found out more info about my motor. It is in the 280 to 290 hp range and is safe to spin to 5500rpm. with the different props I have tried I am thinking somewhere in the 23p range and larger in the 14 1/2 range. any ideas There is a 23p 14 1/4 ballistic on CL I am thinking I will try and pick up to try. Any one have one or try one before? What could I expect?
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Get your a-- to Red Wing and you can try my turbo!
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you sound crabby go back to sleep and I will see you this evening
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So I tried Tim's Turbo 23p and I am still at 60mph with about 4,900rpm So the search is still on. I would like to run WOT at about 5,400 rpm Anyone have any other suggestions for Size and Pitch
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http://www.getaprop.com/content-product_info/product_id-9455/powertech_ofx_3_propeller_mercruiser.html (http://www.getaprop.com/content-product_info/product_id-9455/powertech_ofx_3_propeller_mercruiser.html)
I'd think you should try one of these babies, I'd guess your speed lower 60's @ 5200/5300
I plugged it into the prop & speed calculator @ 5300 rpm 63mph with 11% slippage, which is pretty good.
what the prop calculator don't take into concideration is performance prop mods, like cup, rake, and diameter,
but this new style PowerTech is the best performing prop I have run.
But .. keep in mind that if you want to turn that much rpm, just do it for short bursts, the Mercruiser drives don't like extended runs at rpms over 5000 .. heats up the upper gear case, not good
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Red what pitch are you thinking? 23? Also what Diameter?
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I'd suggest the 15 1/4 diameter with 21 pitch
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Picked up a 22P lazer2 for 125.00 today I might even go get the 18 this weekend so I can try it out.
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Check the hub diameter on your 22" Laser II to see if it fits your gear case. The even pitches are for the small hubs, and the odd pitches for the larger hubs.
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This is an old thread but looks like a good one... so I hope everybody is OK if I add to it rather than start a new one.
My 1979 CVX 18 has the stock Mercruiser 305 228/Alpha 1 configuration, aside from a recent upgrade to an electronic ignition. My exhaust is just a straight tube now (no bellows, more on that later).
With a 4-blade Mercury Spitfire 14 x 21 I am getting max speeds of 50-52 mph regardless of passengers/fuel and otherwise somewhat smooth boating conditions (wind, water etc). The boat is maxing out at those speeds just a shade over 4,000 rpm.
Does this seem about right?
It sure gets out of the hole fast and corners like I'm in a movie.
I won't be pulling skiers, mostly cruising. Are the suggestions above still good if I'm looking for more top end? Any new ideas?
Thanks in advance!!
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50-52 mph seems low, but it's the rims that seem more concerning. Your wot rpms should be around 4600-4800. Try a smaller diameter 3blade in 21p. Prop testing is an artform all its own. Best best is to find a shop or friends that will let you test different props.
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Try a laserII in a 21 pitch. They are 13 3/4 dia. I run one on my cvx18
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1981 Mercury 228 spec. should be the same as a 1979 or 1980 228 MC.
If your using your speedo, might be off by a few MPH.
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Thanks guys! Any recommendations on where to buy the laser II? Any good online stores etc?
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You could also try a Quicksilver Lightspeed, same prop not as highly polished.
You can find Laser II's used on Craigslist or eBay for about $200 to $300.
New there about $500 to $600
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Thanks Hyper!