Thread subject: Whaler Central - Boston Whaler Boat Information and Photos :: 13 sport water spray issue
Posted by Slickityd16t on 03/07/12 - 7:48 AM
#1
I'm having a big issue with water flowing over the transom from under the motor bracket while cruising. It's a 86 and I have not seen the issue before. My 2000 johnson 40 hp is mounted it the same location as last year when I didn't have the issue. The only thing that is different is that the tilt/trim motor is moved to postion number 3 on the bottom of the bracket.
Posted by CES on 03/07/12 - 7:51 AM
#2
Since you changed the tilt angle, you're probably getting spray from the different angle. Have ya thought about raising your motor ont he transom?
Edited by CES on 03/07/12 - 7:52 AM
Posted by thegage on 03/07/12 - 7:52 AM
#3
I don't quite get what you're describing. The title of your post says "water spray", which leads me to think the motor is mounted too low down and is creating a rooster tail/spray, some of which comes over the transom; however, you also says "water flowing" which seems to me to mean a lot more water than just spray.
Also, what is "position number 3 on the bottom of the bracket"? Do you mean the tilt lower-limit pin?
John K.
Posted by Slickityd16t on 03/07/12 - 8:40 AM
#4
I tried mounting the motor up one hole the result was the same. The tilt/trim motor mounting pin was moved to the most verticle postion so it puts less stress on the system while cruising.
Posted by burtim on 03/07/12 - 2:52 PM
#5
Has this boat been kept in the water? Is it possible there is water in the hull and the boat is setting lower than in the past?
Posted by Geo on 03/07/12 - 4:21 PM
#6
This sort of problem can occur if you are using a long-shaft 20" motor on a older small Whaler hull that is designed for a short-shaft 15" motor. What sort of motor do you have?
Posted by John Fyke on 03/07/12 - 4:44 PM
#7
Where does the cavitation plate line up with the keel? You still may have the motor mounted too low.
Posted by Slickityd16t on 03/07/12 - 9:32 PM
#8
The boat has been kept out of the water. The motor a 2000 johnson 40hp is a 20" shaft. The cavition plate was almost dead even with the keel when i noticed the problem now it is 1 inch lower.
Edited by Slickityd16t on 03/07/12 - 9:34 PM
Posted by thegage on 03/07/12 - 10:07 PM
#9
The motor's definitely too low.
John K.
Posted by CES on 03/08/12 - 2:47 AM
#10
Slickityd16t wrote:
The boat has been kept out of the water. The motor a 2000 johnson 40hp is a 20" shaft. The cavition plate was almost dead even with the keel when i noticed the problem now it is 1 inch lower.
That's your problem, you need to raise your motor on the transom so that your Cav plate is at least an inch higher than the bottom of the boat.
Posted by John Fyke on 03/08/12 - 3:40 AM
#11
Raise the motor two more notches.
Posted by Slickityd16t on 03/08/12 - 7:02 AM
#12
CES wrote:
Slickityd16t wrote:
The boat has been kept out of the water. The motor a 2000 johnson 40hp is a 20" shaft. The cavition plate was almost dead even with the keel when i noticed the problem now it is 1 inch lower.
That's your problem, you need to raise your motor on the transom so that your Cav plate is at least an inch higher than the bottom of the boat.
But it never did it before mounted on the bottom hole. Does everybody else here have theirs mounted 2 holes up?
Posted by Slickityd16t on 03/08/12 - 7:08 AM
#13
I also wonder if it could the hydrofoil I have installed
Posted by butchdavis on 03/08/12 - 7:54 AM
#14
Yes, it could.
Posted by John Fyke on 03/08/12 - 8:06 AM
#15
I'm not a fan of hydrofoils at all.
Posted by Brooksinct on 03/08/12 - 10:13 AM
#16
Why did you put a hydrofoil on it?
Posted by John Fyke on 03/08/12 - 10:30 AM
#17
If your motor is rigged right you will not need a hydrofoil. Period.
Posted by CES on 03/08/12 - 11:08 AM
#18
Slickityd16t wrote:
I also wonder if it could the hydrofoil I have installed
The back spray has everything to do with the hydrofoil you installed.
Once you give us all the information, we're more able to help you out with your problem.......instead of us having to peel back the onion and find out what's been going on.
If I were you, I'd take that thing off and set up your motor correctly and you'll be fine.
Posted by thegage on 03/08/12 - 11:17 AM
#19
Slickityd16t wrote:
I also wonder if it could the hydrofoil I have installed
Just like an episode of Car Talk: "Oh, did I forget to mention that the Check Engine Light is On?"
Posted by John Fyke on 03/08/12 - 11:24 AM
#20
Just like an episode of Car Talk: "Oh, did I forget to mention that the Check Engine Light is On?
Exactly.
Posted by Slickityd16t on 03/08/12 - 11:39 AM
#21
I've been out of town and I forgot it was still on. It came with the boat so ill just toss it. Thanks for the help guys.
Posted by Slickityd16t on 03/08/12 - 1:20 PM
#22
Also it didn't do it last year when I test drove it. Ill go out tomorrow for another test ride. Also with the motor level the plate is dead even with the keel.
Edited by Slickityd16t on 03/08/12 - 8:26 PM
Posted by Slickityd16t on 03/09/12 - 2:19 PM
#23
Well I took it for another try foil off and raised 2 holes still does it just as bad. It's got to be from moving the lower mounting pin on the tilt/trim system.
Posted by Phil T on 03/09/12 - 3:09 PM
#24
Let's be clear.
Slick- are you referring to the trim rod position, not the engine bracket positon on the transom?
Posted by Slickityd16t on 03/09/12 - 3:42 PM
#26
Phil- Yes its the trim position rod. I thought about moving it back but with the shape of the BW transom its better for the trim system to be mounted in the third hole. I can take a picture to show what I have done if it will help.
Joe- I tired the 1,2,3 holes on the engine bracket with the same result.
Edited by Slickityd16t on 03/09/12 - 3:45 PM
Posted by CES on 03/09/12 - 5:47 PM
#27
Take a picture with your engine in the down position. Be sure to take it from the side showing the cavitation plate on the motor in relation to the boats bottom of the transom please.
Upload the picture to your personal page.
Edited by CES on 03/09/12 - 5:48 PM
Posted by Slickityd16t on 03/16/12 - 9:10 PM
#28
CES wrote:
Take a picture with your engine in the down position. Be sure to take it from the side showing the cavitation plate on the motor in relation to the boats bottom of the transom please.
Upload the picture to your personal page.
Picture uploaded sorry it took me so long.
Posted by Joe Kriz on 03/16/12 - 9:15 PM
#29
The engine does not seem to be mounted high enough....
What hole is this mounted in on the bracket in the photo?
Posted by Slickityd16t on 03/16/12 - 9:19 PM
#30
Joe Kriz wrote:
The engine does not seem to be mounted high enough....
What hole is this mounted in on the bracket in the photo?
First hole. I still wonder where everbody else has there's mounted.
Edited by Slickityd16t on 03/16/12 - 9:21 PM
Posted by CES on 03/17/12 - 6:50 AM
#31
It's clear in the picture that your Cav plate (the bottom plate in the picture) is to low and while on a plane, would be under the waterline.
If your motor is mounted on the transom in the first hole, you'll need to raise your motor two holes on the transom. Ideally you want your motors Cav plate (when the motor is in the down position) to be locate about one inch higher than the bottom of the boat.
Hope this helps.
Posted by Slickityd16t on 03/17/12 - 9:47 AM
#32
It does help thank you
Posted by Joe Kriz on 03/17/12 - 10:42 AM
#33
If you raise it up 2 holes, it will raise the motor 1 1/2 inches....
That should be just about right as Cliff mentions...
Your engine would then be mounted 2 holes up instead of all the way down.
http://www.whalercentral.com/articles...cle_id=106
Posted by John Fyke on 03/17/12 - 11:55 AM
#34
Joe Kriz wrote:
If you raise it up 2 holes, it will raise the motor 1 1/2 inches....
That should be just about right as Cliff mentions...
Your engine would then be mounted 2 holes up instead of all the way down.
http://www.whalercentral.com/articles...cle_id=106
Just what I said on the first page.
Posted by Joe Kriz on 03/17/12 - 12:05 PM
#35
He also said he was trying holes 1, 2, and 3...
but he was also using the "hydrofoil" at that time...
He has now taken that off... and obviously lowered the engine all the way down....
Posted by Slickityd16t on 03/17/12 - 3:45 PM
#36
I tried in all 3 holes with and without the foil with the same result
Posted by Joe Kriz on 03/17/12 - 3:54 PM
#37
I see a transducer on the bottom of the transom....
Try removing the transducer temporarily and raising your engine 2 holes up...
If you still get too much spray, then go up all the way and try that.
Posted by Slickityd16t on 03/17/12 - 4:02 PM
#38
I just made a blockoff plate the goes below the tilt trim motor. I think that should work.
Edited by Slickityd16t on 03/17/12 - 4:02 PM
Posted by Joe Kriz on 03/17/12 - 4:15 PM
#39
I think you are complicating things.....
I suggest staying to the basics or you are going to be on your own as no one will be able to help you redesign the hull....
Posted by thegage on 03/17/12 - 4:21 PM
#40
There seems to be some real confusion here. I suspect that the trim pin is all the way in because weight on the stern is causing proposing. This puts the AV plate at an angle to direct more spray back at the stern. Plus, as noted, the sending unit looks like it's mounted too low, which probably adds to the spray.
John K.
Posted by John Fyke on 03/17/12 - 5:26 PM
#41
You can angle the engine all you want it won't matter. Just raise the motor all the way up.
Posted by Slickityd16t on 03/21/12 - 2:34 PM
#42
The motor is hole 3 now. Took it out today at full throttle it hits the limiter, and sounds like its not getting enough water during any small amount of wake, speed has also dropped off. I think it is way under proped. Right now it has a Solas 12x17. I bought a used SST 11.25X21 hopefully I won't be having the same issues with it as well.
Posted by Geo on 03/21/12 - 5:28 PM
#43
If 3 holes up does not solve the problem, what else can fix this issue? Maybe the hull is warped? Might be time to find another 13 footer?
Posted by Slickityd16t on 03/21/12 - 6:35 PM
#44
Geo wrote:
If 3 holes up does not solve the problem, what else can fix this issue? Maybe the hull is warped? Might be time to find another 13 footer?
It's not spraying anymore, sorry I forgot to say it. But I have a new set of issues as stated in my previous post.
Posted by Phil T on 03/22/12 - 6:26 AM
#45
Slick -
When you raise the motor, the WOT rpm's increase since there is less drag from the lower unit. Typically, owners report an additional 150 rpm increase for each bolt hole rise.
Every motor has a maximum rpm and a recommended range for WOT. Having to change the prop size is typical after raising the motor.
Prop sizes are
not universal across brands. The best thing to do is keep the diameter but change the pitch.
We need to know the WOT rpm and speed (by GPS) to help you determine the correct size. Also noting the load of gear, fuel and passengers is important.
Posted by Slickityd16t on 03/22/12 - 1:53 PM
#46
Phil T wrote:
Slick -
When you raise the motor, the WOT rpm's increase since there is less drag from the lower unit. Typically, owners report an additional 150 rpm increase for each bolt hole rise.
Every motor has a maximum rpm and a recommended range for WOT. Having to change the prop size is typical after raising the motor.
Prop sizes are not universal across brands. The best thing to do is keep the diameter but change the pitch.
We need to know the WOT rpm and speed (by GPS) to help you determine the correct size. Also noting the load of gear, fuel and passengers is important.
29.1 Mph GPS 6k RPM don't know the rev's when it would cavitate at full throttle
13 Gal of fuel under the middle seat
190 Lbs Driver
50 Lbs of gear
I also have 55-hp carbs, head and boysen reeds waiting to be installed.
The problem is I already have the largest 3 blade prop I can find and it's the solas 12x17
Posted by Slickityd16t on 03/22/12 - 5:16 PM
#47
I also get alot of blowout, turns wake it doesn't take much.
Posted by CES on 03/22/12 - 7:09 PM
#48
It sounds like to me that you need to lower your trim/tilt. Do you have a manual or power trim??
Posted by Tom W Clark on 03/22/12 - 7:20 PM
#49
Try a 11-3/4" x 17" Stiletto Triad 3.5; it's probably the only propeller made that will tolerate that high of a mounting. If that pitch is not enough, try the 11-3/4" x 19" size.
Posted by Slickityd16t on 03/22/12 - 9:11 PM
#50
CES wrote:
It sounds like to me that you need to lower your trim/tilt. Do you have a manual or power trim??
Power trim. But remember I moved the lower mounting pin to the 3rd position or most vertical.
Posted by Slickityd16t on 03/23/12 - 3:50 PM
#51
Tom W Clark wrote:
Try a 11-3/4" x 17" Stiletto Triad 3.5; it's probably the only propeller made that will tolerate that high of a mounting. If that pitch is not enough, try the 11-3/4" x 19" size.
If my SST 11.25 x 21 doesn't do the job I will give it a try thanks for the tip Tom.
Posted by Slickityd16t on 03/25/12 - 1:36 PM
#52
Still having massive blowout problems. It's almost as bad with new SST prop. Rpm's are down speed is barely higher. Maybe I should try putting the lower trim mounting pin back to the lowest setting. I don't want to buy another prop if I don't know for sure it will work. I just can't afford it
Posted by Joe Kriz on 03/25/12 - 1:46 PM
#53
If you have power trim and tilt, that manual pin should be in the lowest hole...
Posted by Bake on 03/25/12 - 2:43 PM
#54
If I were a betting man I would say there is no prop that will not blow out with your motor that high. As Joe mentioned the pin should be at the bottom hole so that you can trim the motor in all the way. But I would say you will find that unless you are running in a straight line all the time any trim at all will blow the prop out when you make turns.
How high is the anti cavatation plate from the bottom of the boat now?
Posted by Bake on 03/25/12 - 3:59 PM
#55
One more thing I think about is even though I have never had 13 footer my 15 has some spray until I start trimming the motor out. If yours gets better as you trim the motor out while on plane you may want to look into a mounting wedge. The slant on the 13 transom is pretty extreme. You might be able to put a little mounting wedge in there and let the motor back down a hole.
Posted by Slickityd16t on 03/25/12 - 6:02 PM
#56
Bake wrote:
If I were a betting man I would say there is no prop that will not blow out with your motor that high. As Joe mentioned the pin should be at the bottom hole so that you can trim the motor in all the way. But I would say you will find that unless you are running in a straight line all the time any trim at all will blow the prop out when you make turns.
How high is the anti cavatation plate from the bottom of the boat now?
Its like an inch above right now
Posted by Bake on 03/26/12 - 2:39 AM
#57
thats not so bad your prop should bite at that height.
Posted by CES on 03/26/12 - 3:44 AM
#58
Joe Kriz wrote:
If you have power trim and tilt, that manual pin should be in the lowest hole...
X2
You should be able to trim your motor down more than you're able to do with the pin in the last (closest to the transom) hole.
Posted by Slickityd16t on 03/26/12 - 11:12 AM
#59
I moved the pin back down to the stock position hopefully I can go for a test run tomorrow before work.
Posted by Slickityd16t on 03/27/12 - 10:54 PM
#60
Well it doesn't cavitate as bad now. But if I move the trim to try and get the bow out of the water it cavitates again. So I moved the motor to the second hole and the tilt pin to the the middle postion.
Posted by Joe Kriz on 03/27/12 - 11:08 PM
#61
Slickity,
That pin should always remain in the lowest hole...
That is a manual tilt pin for motors that don't have power trim & tilt..
You motor has power trim & tilt....
So, leave that pin in the lowest hole and forget about it...
It does absolutely nothing for you....
Disclaimer:
There are other things to use that pin position for but this is not one of them....
Leave the pin in the lowest hole....
Posted by Tom W Clark on 03/28/12 - 7:12 AM
#62
Joe is correct. Any outboard with power trim-n-tilt does not even need a tilt pin, but I like to have one in the lowest hole just on case the power trim fails and I need to manually drop the motor down to operate it. In that case you move the pin where you want it but otherwise it should be in the lowest hole so as not to limit the range of motion of the outboard.
The whole point of power trim is to allow you the change and angle of the motor for varying conditions. Generally you will want the motor tucked in when accelerating onto plane and trimmed out the faster you go to lift the bow.
A 2000 Johnson 40 has four sets of mounting bolt holes. On a 13 footer the motor should be bolted on with the THIRD set of holes, that is, "Two Holes Up". This motor mounted all the way down on the transom will almost certainly cause a lot of drag and spray.
The SST line of propellers is good, though very old at this point. It is not known for great grip at high mounting heights so it is no surprise it is not gripping with the motor mounted all the way up. The only prop I recommend for operation at the highest mounting height is the aforementioned Stiletto.
Posted by Slickityd16t on 03/28/12 - 3:02 PM
#63
Well I do appreciate everybody's help. I was able to hit 32.1 mph today, I couldn't get enough of the boat out of the water to go any faster before it started to cavitate again. I will definately keep the Stiletto prop in mind just wish I could try it before I buy. So I will have to decide where I want to go from here. Thanks again.
Posted by Tom W Clark on 03/28/12 - 3:08 PM
#64
One more thought: You *have* removed the foil from the motor, haven't you?
A Sport 13 with a 2000 Johnson 40 should easily be capable of 35 MPH and maybe even 37-38 MPH with power trim. 32.1 MPH makes me suspicious of something being wrong with the set up. If that foil is still on there, that's part of the problem.
Posted by Tom W Clark on 03/28/12 - 3:14 PM
#65
What was the engine speed today when you hit 32.1 MPH? Do you have a Tachometer?
Posted by Joe Kriz on 03/28/12 - 4:24 PM
#66
From one of his prior posts.
Right now it has a Solas 12x17. I bought a used SST 11.25X21
It's been many years since I have owned a 13', but it seems a 21 pitch prop is way over propped. Anyone disagree?
Also, we have no way of knowing how good this used prop is.
As Tom mentions, do you have a tach installed?
This would tell us much needed information.
I also would try and find a good prop shop that will "Loan" you a prop to try before buying.
His boat looks clean... No bottom paint.. Appears to sit in the water good.
Posted by Geo on 03/28/12 - 4:46 PM
#67
Based on what you have told us, I think your hull is warped. A pocket of air is forming under the hull as you are underway, and no amount of correction at the prop, or at the engine height, is solving this problem. This can happen if the boat is stored for a long time in a bad position.
Posted by Slickityd16t on 03/28/12 - 6:28 PM
#68
It was 5000 rpm. I doubt the hull is warped it's been on a trailer when its not in the water. I also just bought a stiletto triad prop.
Posted by John Fyke on 03/28/12 - 6:30 PM
#69
Geo wrote:
Based on what you have told us, I think your hull is warped. A pocket of air is forming under the hull as you are underway, and no amount of correction at the prop, or at the engine height, is solving this problem. This can happen if the boat is stored for a long time in a bad position.
If his hull is warped I highly doubt he'd even hit 32mph.
Posted by Tom W Clark on 03/28/12 - 6:44 PM
#70
I see no evidence of a warped hull.
Joe -- You are right, a 21" prop is w a y too much pitch for that boat/motor combination.
The 2000 Johnson 40 uses a 2.42:1 gear ratio and 32.1 MPH with a 21" pitch prop is only 4300 RPM if you assume 10 percent slip. Hell, if the prop slipped so badly that there was 20 percent slip, the poor motor couldn't have reached more than 4800-4900 RPM. That motor should really reach 5000-55500 RPM at WOT if it is propped correctly.
Again, I recommend the 11-3/4" x 17" Stiletto Triad 3.5, a propeller with a lot of grip and inexpensive too. For the price of the foil and the used SST, the Stiletto probably would have solved all the problems and got the boat to 35 MPH where it should be.
Posted by Tom W Clark on 03/28/12 - 6:46 PM
#71
Oh, a few posts snuck in while I was composing that.
OK, 5000 RPM at 32.1 MPH with a 21" pitch prop through 2.42:1 gears is 21.9 percent slip. No wonder the prop was loosing grip and ventilating!
Posted by Joe Kriz on 03/28/12 - 6:55 PM
#72
Slickityd16t wrote:
It was 5000 rpm. I doubt the hull is warped it's been on a trailer when its not in the water. I also just bought a stiletto triad prop.
He says he just bought the Triad prop but didn't tell us what size...
17 pitch, 19 pitch, or other...........?????
Man, I feel like a dentist here pulling teeth...
Please, give us all the information you can so we don't have to keep on guessing....
Posted by Slickityd16t on 03/28/12 - 7:44 PM
#73
Sorry I got the 19 pitch since I'll be put on 55 hp head and jets
Posted by blacksmithdog on 03/29/12 - 4:28 AM
#74
Just as a comparison, my 13' standard with a 25 Merc 4 stroke runs in the high 20's per GPS depending on conditions and load.
Posted by dgoodhue on 03/29/12 - 5:45 AM
#75
Slickityd16t wrote:
Sorry I got the 19 pitch since I'll be put on 55 hp head and jets
Are you 100% sure those mods are going to up you hp to 50-55hp and will it shift your rpm range higher? On a 15' whaler I have a 19p stiletto & 21p sst with a motor w/ 2.42:1 gear ratio. My rpm range is a little higher @ 6000 rpm but I hit 47mph @6200rpm with those brands of props (mine are different diameters)
If you can get the to motor spin to 5500rpm, your boat will speed should be around 42mph. That is not goin to happen with your 40 on a 13'. I looked up a 2000 50hp 2 stroke and the rpm range is to 6000 rpm. I don't think your boat will run 45 mph with 50 or 55 hp either.
Posted by dgoodhue on 03/29/12 - 6:26 AM
#76
Also the right prop for 40 @5500 is the right prop for 50 @6000 for a 13' whaler.
Posted by Phil T on 03/29/12 - 6:56 AM
#77
I agree with Joe, this is like wack-a-mole.
Slick, we need to take baby steps and solve one issue without making other changes. Right now we are trying to help you with motor height and prop size,
before any "engine enhancements".
We are 74 posts along. The spray issue is resolved (post 44) but we now have the correct prop question.
Please do a test run with the Triad 19p prop and report speed via GPS with WOT rpm's.
Please don't do any changes to the engine before or after the test.
At Wot you should use the power trim. In applying trim you should watch your GPS speed. As you trim out, your speed will slowly increase with no change in RPM's. When speed starts to slowly decrease with more trim, back down the trim slightly. That is the optimum trim point.
Edited by Phil T on 03/29/12 - 7:04 AM
Posted by Tom W Clark on 03/29/12 - 7:16 AM
#78
Triad 19 inch is going to be too much.
Does anybody know if he took the foil off or not? He never said as far as I can see, but this thread is getting ridiculously long and maybe I missed it.
Posted by Slickityd16t on 03/29/12 - 10:53 AM
#79
The foil is off. I will not install my upgrades until I get the prop situation close to solved. If the rpm's are a bit low with the new triad 19 pitch I can deal with it, as when the upgrades are installed should bring the power up enough to bring the rev's to optimum level.
Edited by Slickityd16t on 03/29/12 - 2:36 PM
Posted by Slickityd16t on 03/29/12 - 2:43 PM
#80
dgoodhue wrote:
Slickityd16t wrote:
Sorry I got the 19 pitch since I'll be put on 55 hp head and jets
Are you 100% sure those mods are going to up you hp to 50-55hp and will it shift your rpm range higher? On a 15' whaler I have a 19p stiletto & 21p sst with a motor w/ 2.42:1 gear ratio. My rpm range is a little higher @ 6000 rpm but I hit 47mph @6200rpm with those brands of props (mine are different diameters)
If you can get the to motor spin to 5500rpm, your boat will speed should be around 42mph. That is not goin to happen with your 40 on a 13'. I looked up a 2000 50hp 2 stroke and the rpm range is to 6000 rpm. I don't think your boat will run 45 mph with 50 or 55 hp either.
I sure the mods will bring me up higher. The only difference in the 40,50, and 55 are the jets between all three, and the head on the 55 which I have. Also the 55 has a bigger midsection and gearcase. The midsection section exhaust ports I'm pretty sure are the same size. The only power killer is going to be the through hub exhaust since 55hp's have a larger hub.
Posted by Geo on 03/29/12 - 5:06 PM
#81
Trying to modify that engine so its output is 55 h.p. sounds like wack-a-mole for sure. Go ahead and try it, but if your boat is still performing at 30 m.p.h., I'll bet you anything that the engine is not the problem and it is the boat's hull being warped that is the issue. Is your boat nose-diving? If so, it may be warped. You can not see the warp from the vantage point of a trailer. You need to flip the boat over and check the hull for delamination. If there is delamination, you will be able to detect large "soft spots" in the hull where the outer hull is no longer bonded to the inner hull. Also, there is no way on earth that you would ever need a 19 inch pitch prop for a 40 h.p. on a 13 foot Whaler. Normal would be about 13 or 15 inch.
Edited by Geo on 03/29/12 - 5:12 PM
Posted by Tom W Clark on 03/29/12 - 6:36 PM
#82
...there is no way on earth that you would ever need a 19 inch pitch prop for a 40 h.p. on a 13 foot Whaler. Normal would be about 13 or 15 inch.
Nope. A 2000 Johnson 40 on a 13 footer would normally use a 17" pitch prop but, of course, that also depends on exactly what model of propeller you are talking about. A 13" pitch prop on this boat, of any brand or model, would be a disaster.
There is NO WAY you can generalize about what pitch is needed simply by horsepower. Different outboards of the same horsepower use different gear ratios, have different engine speed ranges and use different size gearcases.
Be very careful when making generalizations and never bother to offer propeller sizing ad=vice unless you explain exactly what model of propeller you are talking about.
Posted by Slickityd16t on 03/29/12 - 8:38 PM
#83
Geo wrote:
Trying to modify that engine so its output is 55 h.p. sounds like wack-a-mole for sure. Go ahead and try it, but if your boat is still performing at 30 m.p.h., I'll bet you anything that the engine is not the problem and it is the boat's hull being warped that is the issue. Is your boat nose-diving? If so, it may be warped. You can not see the warp from the vantage point of a trailer. You need to flip the boat over and check the hull for delamination. If there is delamination, you will be able to detect large "soft spots" in the hull where the outer hull is no longer bonded to the inner hull. Also, there is no way on earth that you would ever need a 19 inch pitch prop for a 40 h.p. on a 13 foot Whaler. Normal would be about 13 or 15 inch.
I had the hull upside down last year for a bunch of gelcoat repair. Their is nothing wrong with the hull other than the poor color matching I did on the bottom.
Posted by Geo on 03/30/12 - 5:24 PM
#84
You wrote : "Nope. A 2000 Johnson 40 on a 13 footer would normally use a 17" pitch prop but, of course, that also depends on exactly what model of propeller you are talking about. A 13" pitch prop on this boat, of any brand or model, would be a disaster."
Based on my use for 42 years of a 13 ft Whaler, starting with a 40 h.p. Merc in 1970, and then shifting to a 50 h.p. Yamaha in 1986, I'm surprised you believe a 17 inch pitch prop would be correct, but then again, all motors are different, as you point out. Have you tried a 17 inch prop yourself on that boat?
For my Yamaha I am using a 15 inch three-blade aluminum prop and it does fine for 1-3 people in the boat, without the motor running at too low or high r.p.m. I'm just passing along my experience. The 13 inch prop would do O.K. for water skiing but would allow the motor to run at too high an r.p.m. for general use. How a 19 inch prop would be appropriate, I do not know. It might work O.K. for a very light person alone in the boat. Questioning the use of the 19 inch prop was my main point.
Edited by Geo on 03/30/12 - 5:28 PM
Posted by Tom W Clark on 03/30/12 - 6:04 PM
#85
I'm surprised you believe a 17 inch pitch prop would be correct...
Why?
Posted by dgoodhue on 03/30/12 - 7:28 PM
#86
Your 50hp Yamaha has a 1.85:1 gear ratio and the motor in question has 2.42:1. Your Yamaha if it had a 2.42 gear ratio would require a 19p prop of the same style to go a similar speed as the 15p you currently have.
Posted by Slickityd16t on 03/30/12 - 8:27 PM
#87
dgoodhue wrote:
Your 50hp Yamaha has a 1.85:1 gear ratio and the motor in question has 2.42:1. Your Yamaha if it had a 2.42 gear ratio would require a 19p prop of the same style to go a similar speed as the 15p you currently have.
Exactly why you can't just look at horsepower. Also gearcase size are large factors, 4-strokes have a bigger case than in the past so prop diameters are different than before.
Edited by Slickityd16t on 03/30/12 - 8:28 PM
Posted by Tom W Clark on 03/31/12 - 7:24 AM
#88
The old 1970 Mercury 402 (40 HP) used a 1.7:1 gear ratio.
The 2000 Johnson 40 uses a 2.42:1 gear ratio.
If you do not understand the relevance of gear ratio, then let's use this as an example.
For a Sport 13 to reach 36 MPH (which is what Whaler said it would do with 40 HP) with the 1970 Mercury 402 and its 5300 RPM redline and 1.7: gear ratio will require a propeller with 13 inches of pitch, assuming about 6 percent propeller slip.
For the same boat to reach the same speed with the 2000 Johnson 40 and its 5500 RPM redline and 2.42:1 gear ratio will require a propeller with 17.8 inches of pitch, assuming the same amount of propeller slip.
I know from personal experience that the Stiletto Triad tends to have low calculated slip so the 17 inch pitch model is what I recommend.
With the 19 inch Triad, the 2000 Johnson will only reach about 4900 RPM at WOT.
Posted by Slickityd16t on 04/03/12 - 11:44 PM
#89
Prop came in today, of course I didn't know the hub was separate.
Posted by CES on 04/04/12 - 3:40 AM
#90
Slickityd16t wrote:
Prop came in today, of course I didn't know the hub was separate.
???? Details please.
Posted by dgoodhue on 04/04/12 - 6:14 AM
#91
CES wrote:
Slickityd16t wrote:
Prop came in today, of course I didn't know the hub was separate.
???? Details please.
The hub isn't included. This Allows the prop to be more universal so it would fit OMC, merc, Yamaha, ect lower units and all you would need to do is change the hub.
Posted by Tom W Clark on 04/04/12 - 7:36 AM
#92
I cannot believe a propeller vendor would have sold you the prop without advising you of the need for the hub. Even online vendors usually force you to select the appropriate hub or check a box indicating you don't need one.
You need the C-012 Guardian SQ-LOK hub kit
Posted by Slickityd16t on 04/04/12 - 11:39 AM
#93
Tom W Clark wrote:
I cannot believe a propeller vendor would have sold you the prop without advising you of the need for the hub. Even online vendors usually force you to select the appropriate hub or check a box indicating you don't need one.
You need the C-012 Guardian SQ-LOK hub kit
I'm right there with you on that.
Glad I ordered the right one.
Posted by Slickityd16t on 04/29/12 - 10:58 PM
#94
Finally took her out today with triad prop, my truck was down all month. Anyway was able to hit 34.3 mph @ 5800 with the motor trimmed up. With it trimmed down where it doesn't cavitate terribly easily 27-28 mph @ 4200-4400. The motor is in the second set of holes. 1 person 190lbs, 7 gallons of fuel, tank is under middle bench.
Edited by Slickityd16t on 04/30/12 - 12:06 PM
Posted by Slickityd16t on 05/01/12 - 6:12 PM
#95
I still seriously wonder if the 14 gal fuel tank in the middle of boat has anything to do with the issues.