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Posts: 1663
Location: Kodiak, AK | What pitch are y'all 619/620/621 owner's with 200's/225's running for props? I know there's a huge spread of possibilities, variances and differeneces, but over at BBC I mentioned that I'm runnin a 23M, maxing out at 40 mph and 4600 rpm, and the responses was basically, "WHOA!" And I was advised to switch to a 19 for a "boat that size." Just curious what other guys with big glass boat where running, so I can get an idea if I'm really that far off, and maybe make some changes before next spring.
Thanks. |
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| Esox,
I have a 620 with 250 etech-ho.
It was propped from Ranger with a Raker II-22 pitch. I thought it was a dog out of the hole and top end was around 52mph. Rpms were to low.
I talked with Eric Olson from Evinrude and he instructed me to get an 8 inch Detwiler internal hydro plate. This is the exact setup he uses.
The boat screams now, hole shot is awesom and top end is 68mph plus, hammer down 5800-6000 rpms, full tourney load with my partner. I know I can get more if given enough lake to adjust and play with the plate.
You just have to play around with were the plate needs to be set at takeoff, once you find the sweet spot your golden.
Its like an entirely different boat since the plate was added.
Good luck
Joe |
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Posts: 58
Location: Oak Island, MN | Joe,
Which plate did you settle on? Looks like an 8" setback manual? Have a modle number?
Thanks,
Frank |
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Posts: 1663
Location: Kodiak, AK | Thanks Joe. So adding a plate, upper your RPM's? I'm obviously new to the pitch/prop/mount experimentation thing. I just want to make this boat as efficient as possible, and right now I think I'm missing out on RPM's and performance. |
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Posts: 2384
Location: On the X that marks the mucky spot | You really are that far off with your setup.
If you're running an old style Ranger hull a plate isn't going to do all that much compared to proping your boat correctly. It's too heavy to really give you more then 1-2 mph. I sell to a jackplate mfg and we've played around with these things a ton over the past few years. You may benefit from raising your motor, but find a prop that gets you in the ballpark first and then play with engine height and jackplates.
You NEED a smaller prop. On the old style 620 and a 225 you should be running a 21-23" prop. If you're only getting 4600rpms I'd start at a 19". Remember, lugging an engine can be worse for it then over reving (to a point). I'd try a 19" Rev 4. That's the prop I've been hearing works the best all around on these hulls. If you want the fastest get a Tempest. Although the Rev 4 is going to be faster when hauling a load and when in rough water as the extra blade will stay hooked up and give you more lift.
Drop me a line if you want and I'll help you where I can. |
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Posts: 1663
Location: Kodiak, AK | By "old" style hull, do you mean the 225hp 620 vs the 250 620? Or do you mean older than that?
I'm running a 23 now, so I think I'll look at the 19, and the motor is mounted on the second to lowest holes, meaning the second to highest position, so I don't think motor height would be slowing me down.
Depending on how long the motor's been lugged like this, where would I see failure show up? Rods? Crank?
Thanks Treats...I may be in touch.... |
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Posts: 75
Location: Aurora, IL. | Esox and Frank,
The plate I use is a Detwiler All-in-One 8" hydraulic. It was recommended because it requires no additional hydraulic hoses running from the bilge area out to the plate. I beleive Bob's also now makes an all in one plate as well.
Check the Detwiler web site; http://www.detwilerjackplates.com/products.htm
I agree with Treats with regard to the process of setting up the boat. Definately start with propping. The reason I went directly to the plate was that I was sure that my setup was exactly the same as Eric's and I new what results I could expect.
Additionally, I would call Ranger and Yamaha to get their opinions as well. I called Ranger and talked with the guy that sets up all their boats and then my dealer recommended talking with Eric Olson the Evinrude representative who also is kind of their R & D guy with engine and boat set ups. The information I got helped formulate the end result.
Hope this helps!
Joe |
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Posts: 75
Location: Aurora, IL. | Esox I sent you a PM.
Joe |
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| isn't that Sleds old boat? it only hits 40? something is wayyy off. you want to be running your rpms in the 5600-5800 range with a wide open throttle. you first need a much smaller pitch prop and start from there. |
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Posts: 1663
Location: Kodiak, AK | It is Sled's old boat. And yes, I agree, I'm way low on RPM's and speed. But until talking to the boat nuts over at BBC, I thought I was right where I should've been. I was wrong! I think I'll be switching to a 19 prop before next year. Jon told me that's the original prop, so either he ran it like that, or something is askew in the powerhead and I've lost my rpm's there.
Sled, if you're reading this, I sent you a couple of emails....
Edited by esoxfly 12/16/2008 11:36 AM
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Posts: 58
Location: Oak Island, MN | Run N Gun.............THANKS! |
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Posts: 311
| 2001 620 with a 225 yamaha(3.1 L), 23 tempest, runs 58 at 5700 rpm, with 2 guys and full of gear. I would have to say that the motor might not be running on all cylinders. These set-ups are almost identical. 18 mph and 1000 rpm is a HUGE difference. Also does not have a jackplate.
Edited by Smokin Joe 12/17/2008 5:25 AM
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Posts: 1663
Location: Kodiak, AK | I'm working on it. I'm looking at fuel pumps first. They're a common issue with these motors and an easy fix. Just talked to guy who lost 700 rpm on his when a diaphram tore and he didn't know about it. It was a gradual thing. Got it fixed and everything was back to normal. Alot of guys consider fuel pumps to be routine maintenance every few years. I figure that motor is due. |
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Posts: 58
Location: Oak Island, MN | Esoxfly,
Here is a site that specializes in E-TEC motors. I don't like to post someone elses site, but this one is pretty generic. Great source of E-TEC technical data.
http://forums.etecownersgroup.com/mb/barnaclebill |
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Posts: 1663
Location: Kodiak, AK | Cool. Is there a VMax owner's group site you know of? I've been hanging out in the Yamaha section at BBC as of late. (I'm a Yamaha guy.  )
Edited by esoxfly 12/17/2008 1:58 PM
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Posts: 3480
Location: Elk River, Minnesota | Hiya,
Something is definitely NOT right with this set-up. Not sure of only one thing, though...what is the gear ratio for your lower unit?
I did a quick calculation with the numbers you listed and used a gear ratio of 1.81:1. this gave me theoretical speed of 55mph. This would mean you have a slip factor of 27% which is below where it should be for that boat. A slip factor of 12% to 15% is more typical...and in some cases, that slip factor can be as low as 8%.
I would agree that the lugging of the motor sounds right...and going down to a 19 pitch cupped steel is definitely the right move... By doing so, you should see an increase in roughly 150 to 200 RPM's per inch of pitch...thus going down 4 inches in pitch will give you anywhere from 600 to 800 more RPM's. That translates into much more power since the engine is turning faster as it compares to the pitch of the prop. Assuming a 700 RPM increase, you would be seeing a much better hole shot, and theoretically a speed of somewhere around 47mph. This is given a 10% slip factor.
Something is definitely not right. Assuming this boat is right around 2100 pounds, we should be seeing numbers right around that 46mph to 48mph given the RPM range is maxed at 5500. Generously, if we went with an increase of 900 RPMs with a 19 pitch prop, and a 10% slip factor, you would be seeing 49 mph.
I think a change in prop is in order. One that has a good amount of cup to it... I'd look at what treats has said with his recommendation. The tempest prop will be the most aggressive, which will lift the entire boat more out of the water, which will help quite a bit. I would also consider looking into the yamaha pro series of props as well. Definitely something with a vented hub to give you better hole shot.
I don't think there is anything wrong with the engine... I think it is just over-propped..
Definitely checking the fuel pump for issues is a good thing too...but by the numbers from the yamaha specs, that motor is to run as a max at 5500, with a gear ratio of 1.81:1, if something is wrong engine-wise, it could potentially show here as well.
Suggestion: Leak-down test on the powerhead as well, a good run of mercury powertune through the engine in spring, fresh plugs after that, and check that diaphram on the fuel pump. Can't hurt. If all of those come back decent, then start playing with props... I would think if something is wrong with the pump, it would show on your plugs... If something electrical is wrong (like a failing power pack) it would show on the plugs as well...
My gut says prop, but until you get in there and check, who knows...
steve
Edited by VMS 12/18/2008 8:26 AM
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Posts: 1663
Location: Kodiak, AK | Wow Steve, that's more direct and undiluted info in one spot than I've received anywhere. Thanks!
The boat is in the shop right now. I buzzed a rock a few weeks ago with the prop only, and it's fine, but I'm filing a claim to get it documented that I hit something in case I throw a tooth or something next summer. But while it's in there, he's going to check compresssion and such again. After I get it back from there, I'll be changing the fuel pumps. Word on the street is that it's just as fast and almost as cheap to just change the whole pump and not even mess with the diaphram.
Lemme ask you this- how many RPM could I possibly lose by not trimming the boat correctly while on plane? I was schooled the other other day about lifting the prop on plane until it starts to let go, and then just back down from there. I pretty much put the prop down and leave it there, not messing with trim like I should (didn't know any better). Dude over on BBC said you could lose 300-500 not trimming the motor correctly.
I had to weigh the rig this past summer for my PCS move, and on a scale, the boat and trailer is 4650. How much does that trailor weigh? I've got the feeling the boat is more than 2100. How much will that change things, prop-wise?
Thanks guys. I think I'm getting there and narrowing this down, which is good. Yous guys is awesome.
Danged ice! It'll be April before I can put this to work. |
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| wait a minute, so you are saying you were wide open throttle with the motor trimmed all the way down and that is the speed you were hitting? That changes EVERYTHING.
The difference between WOT trimmed all the way down on flat water on my boat and all the way up could be as much as 10mph.
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Posts: 13688
Location: minocqua, wi. | when you trim that boat out you should get 5200 rpm's ... and top speed around 47-48mph on the gps. if the motor is buried in the water you will lose rpm's huge. so, it sounds like you might be able to solve it by propping it differently and then finding the spot on the trim dial that peaks the rpm's.
i'm hopeful obviously that you don't have a problem that's bigger, but that motor and boat jump out and get flat fast which was my main interest for waters i fish ... trimmed it's always been fast enough, but it's no 55mph + motor/boat combination and never was, but then i don't spend that much time on really big water and don't drive over 40ish much at all.
Edited by jonnysled 12/18/2008 1:18 PM
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Posts: 1663
Location: Kodiak, AK | The more I talk to you guys, and talking to you Jon, I'm more and more convinced that this is largely operator error, and maybe a bit to much prop. I don't run the motor burried, but I didn't know that trimming could affect RPM that much...I just didn't know any better. I trim it down when I'm up on plane, but don't mess with it after that. I've probably ran it too low. Ice is here now, so it'll be next spring, but my mind is at ease.
And no Jon, I'm entirely convinced the motor is sound. That friggin motor is a gem. I don't expect it to be 55; heck I thought 40 was good enough for me, but I'll play with it and the prop next spring and go from there. I don't fish Tx's, and just want the boat and motor happy and whatever speed it gives me I'm happy with.
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Posts: 3480
Location: Elk River, Minnesota | Hi esox and company,
Trimming is a constantly changing thing...it all depends on what you are doing with the boat, the conditions you are faced with, and the weight distribution of the boat as well.
When trimming, the most efficient position is found when the boat either starts to porpoise, or you continue to trim up and you start to lose speed and RPM's jump. The latter is definitely one you will notice...especially if you put the boat into a slight turn.
Also of note, if you are not trimming up while on plane, you have a huge amount of "wetted" surface which, with more boat in the water eats speed...and boat efficiency. And...as guest said, if you keep it trimmed down while at speed, there can be as much as 1000 RPM difference from optimum trim angle. As an example, my rig (tin with a 90hp yamaha) would run at 4500 trimmed down when calm, but would turn 5350 while trimmed to optimum. So...lots of room to go if you are trimmed down. If you were trimmed down, I would guess you might have found the steering to be a little stiffer? I would assume you have hydraulic, and having not run a hydraulic steering, I'm guessing there....definitely not sure on that one. I would bet, though that if you turned it would turn on a dime if you cranked the wheel hard enough and that front end would whip around. THAT is a good thing... But...not so good if you are running a straight line.
Trim is constantly changing...when cornering, trimming down allows the bow to help carve the turn. When straight, optimum trim is getting the bow to begin to porpoise, then back down just a touch to settle the bow. Once there, it will need to continually be adjusted for the conditions...more waves and into the wind, trim down accordingly to smooth out the ride. Much of what you do with trim is a "feel" thing...get it to what you are most comfortable with and continue to adjust as conditions do to stay with your comfort zone.
A good way to see the use of trim is to watch some of small outboard racing...not the drag racing, rather the course racing... When they do the helicopter thing along side the boat, and the boat goes into a turn, you can see them trim down, then on the straight, you can see the bow come right up/
Boy...just thinking about all this has got me antsy...I'd love to get in that boat and take a ride!! It's a sweet looking rig and to be honest, I bet it makes an awesome fishing platform.
Steve
Edited by VMS 12/18/2008 9:53 PM
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Posts: 13688
Location: minocqua, wi. | steve brings up a great point on steering ... the more you trim and maximize the rpm's the stiffer and more difficult steering is and especially in turns you learn to dig and eat more water for safety of turning and over time it becomes a "feel" thing ... i guess it's easily taken for granted but something that you'll continue to learn as that boat becomes like a pair of shoes to you.
lots of folks available to help you understand the plusses and minuses on prop selection for motor performance and i think like everything there are trade-offs where you give a little of this to get some of that. just need to know what you're shooting for to make the right selection ...
good luck. oh, and i'd like to take that boat for a spin sometime! |
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Posts: 1663
Location: Kodiak, AK | VMS - 12/18/2008 10:44 PM
...I'd love to get in that boat and take a ride!! It's a sweet looking rig and to be honest, I bet it makes an awesome fishing platform.
Steve
You dang skippy it does. It's like Sled told me when he sold it to me, alot of guys look at it kinda funny when you pull up to the ramp, but every single person that fishes out of it just says, "wow, this boat really makes sense!"
Where's Hastings at? My parents live in Brainerd. Any time you're in the area here in MI Steve, you're welcome aboard. I reckon I could learn more from you just pulling away from the dock than I could on my own the next four years.
You know you got a ride Jon.
Edited by esoxfly 12/19/2008 3:12 AM
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Posts: 3480
Location: Elk River, Minnesota | Hi Jon,
Hastings is just south of the Twin Cities, right about where the Mississippi river becomes the border between Minnesota and that "Other state"  All kidding aside, I do make it up through brainerd a few times through the year...used to spend the summer north of there.
You can darn well bet I'll hold you to that ride if I make it out that way...St. Clair has been one of those lakes on my list to visit sometime. So...I will definitely keep that one on my radar!! Thank you for that!!
Steve |
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Posts: 1663
Location: Kodiak, AK | Oops, I think my grammar failed me above. My last line was address to Sled, who is Jon; I'm Jeff. I bought the boat from him, so he's got an open invite to fish fish with me any time.
But now that's open to you too Steve. Really, if you're in Eastern MI any time June through December (open muskie season) look me up.
Jeff |
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