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Proper Alignment for Twin Engines?

Old 08-24-2020, 06:31 PM
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Default Proper Alignment for Twin Engines?

2019 Parker 2520XLD with Twin Yamaha 200XCAs mounted on a bracket. The question I have is, should the engines be parallel to each other? Nothing is bent; but, it appears the engines are set up to be tailed in towards each other by a few degrees. It's most noticeable when the engines are trimmed all the way up. If one engine is straight up and down the other appears to lean towards it ever so slightly. Trimmed down that would result in the props being towards the centerline of the hull (Keel). It has a SeaStar cylinder on the Starboard engine and a tie rod to the port.
Old 08-24-2020, 06:35 PM
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Some builders and riggers tow the motors in like you said so the prop wake meets a certain distance begins the boat.

The best way in my opinion is too unhook the tie bar when running on plane and adjusting so it lets the other motor run at the desired angle. Obviously you need a compete at helper and fairly calm stretch of water to accomplish this.
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Old 08-24-2020, 06:44 PM
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Yamaha has the motors towed out a tad. Such that the wake from each motor meets at or about 25 ~ 50 feet behind the boat.




Last edited by alloyboy; 08-24-2020 at 06:49 PM.
Old 08-24-2020, 06:52 PM
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That makes sense. This bracket design was a new for 2018 (I think). The engines are spaced further apart than earlier models. I think they are 24-26" inside mount bolt to inside mount bolt. I'll have to take some measurements to see where I'm at. Maybe a run with the port engine disconnected to see where It should be
Old 08-24-2020, 06:55 PM
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Originally Posted by Unevensteven View Post
That makes sense. This bracket design was a new for 2018 (I think). The engines are spaced further apart than earlier models. I think they are 24-26" inside mount bolt to inside mount bolt. I'll have to take a run with the port engine disconnected to see where It should be
Who can determine that is where that it should be? You.

If you do this, please let us know the performance changes (if any) that you see. Make sure that the boat is the same weight, at the same speed with the motors trimmed to the exact same trim angle.

Then be sure and let Parker Boats know that they misadjusted your motors.
Old 08-24-2020, 07:02 PM
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Originally Posted by alloyboy View Post
Who can determine that is where that it should be? You.

If you do this, please let us know the performance changes (if any) that you see. Make sure that the boat is the same weight, at the same speed with the motors trimmed to the exact same trim angle.

Then be sure and let Parker Boats know that they misadjusted your motors.
I did edit my post. First I'll take some measurements as suggested in your first post. Then I'll look at the running disconnected option. I will report back.
Old 08-27-2020, 01:20 PM
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Here are two pictures of my wake. The first is cruise power running 35 mph. The second is full power running 50 mph. Am I missing something or do the engine wakes never meet at either power setting. I measured the toe out and is is exactly 1”. The engines are mounted 38” apart on Center.


Old 08-27-2020, 02:03 PM
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Contender told me they send boats out with motors parallel, neither in or out. An awful lot of people like "toed-in". Yours looks like the "wash" starts immediately behind your motors, maybe meaning that your "toe-out" is causing an immediate merging. Perhaps try toe-in. I think the shape of the hull has something to do with the setting as well.
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Old 08-27-2020, 04:29 PM
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Originally Posted by hotwire_marine View Post
Some builders and riggers tow the motors in like you said so the prop wake meets a certain distance begins the boat.

The best way in my opinion is too unhook the tie bar when running on plane and adjusting so it lets the other motor run at the desired angle. Obviously you need a compete at helper and fairly calm stretch of water to accomplish this.
I did unhook the tie bar while I was running her today. What a weird feeling putting power to the engines knowing I can't control one of them. At the same power settings I didn't notice any difference in the wake or the performance. I was by myself so I couldn't see if the was a misalignment of the bolt holes. Hopefully, tomorrow I will have help and I'll be able to report back on that.
Old 08-28-2020, 09:35 AM
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I ran her today with a friend at the helm and the tie rod disconnected. The engines found their neutral. To be honest I was amazed. I shortened the tie rod as much as I could. The hole was still a half inch too far out. The engines want to run toed in. I guess it’s because they are 2 1/2’ behind the transom on a bracket. The water flow must be moving away from centerline at that distance. Right now the engine are set parallel because I can’t go any shorter on the tie rod. As an aside, I also have the trim anodes mounted neutral.
Old 08-28-2020, 10:57 AM
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Did you notice any improvement on performance?

Originally Posted by Unevensteven View Post
I ran her today with a friend at the helm and the tie rod disconnected. The engines found their neutral. To be honest I was amazed. I shortened the tie rod as much as I could. The hole was still a half inch too far out. The engines want to run toed in. I guess it’s because they are 2 1/2’ behind the transom on a bracket. The water flow must be moving away from centerline at that distance. Right now the engine are set parallel because I can’t go any shorter on the tie rod. As an aside, I also have the trim anodes mounted neutral.
Old 08-28-2020, 11:10 AM
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The steering is easier and there is less spray coming off the engines. Top speed I may have gained 1 mph. As far as the wake, I was able to see a definite point where the wakes joined about 25-30’ behind the boat at cruise speed of 3500 rpms and 27 mph. I also picked up about 2 mph at cruise. 3500 rpm used to be 25 mph.
Old 08-28-2020, 11:40 AM
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That sounds like a positive change. According to the tribal knowledge, you could consider lengthening the con rod back out a couple turns to get the wake convergence to more like 50'. I'd love to see an "after" photo of your wake with the change that you made...

Maybe someone with knowledge of the physics at work here will chime in...
Old 08-29-2020, 05:37 AM
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Originally Posted by k2Freak View Post
That sounds like a positive change. According to the tribal knowledge, you could consider lengthening the con rod back out a couple turns to get the wake convergence to more like 50'. I'd love to see an "after" photo of your wake with the change that you made...

Maybe someone with knowledge of the physics at work here will chime in...
I'll take a picture today. I am assuming because the engines are mounted 2 1/2' behind the transom on the bracket, the water flow at that point has reversed direction and is rolling away from the centerline of the boat. Another factor may be the distance they are mounted apart from each other. They are 38" apart or in other words each is mounted 19" outboard of the boat's centerline. Currently the engines are parallel and the wake meets about 25-30' behind the boat which suggests they need the additional 1/2" of toe in.
Old 08-29-2020, 05:58 AM
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Originally Posted by alloyboy View Post
.

Then be sure and let Parker Boats know that they misadjusted your motors.
You’re always happy to point out manufacturers send their boats out with the wrong props. They are also frequently hung too low from the factory.

It’s not at all hard for me to believe there’s even less attention paid to the toe setting. It would take 1 min of research to just do what the book says (as seems to be the case for the OP) and hours of testing to compare settings and figure out “best.”
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Old 08-29-2020, 06:43 AM
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Originally Posted by Texas 17 View Post
You’re always happy to point out manufacturers send their boats out with the wrong props. They are also frequently hung too low from the factory.
It’s not at all hard for me to believe there’s even less attention paid to the toe setting. It would take 1 min of research to just do what the book says (as seems to be the case for the OP) and hours of testing to compare settings and figure out “best.”
I don't think that I have said that boats are sent out with the wrong props. I think what I have said is that the props that are provided with a new lightly loaded boat will not be the correct props for the boat once it is placed into service and loaded down.

Can some boats and motors experience better performance with testing? Changes? Propeller models, brands, diameters, pitch, etc,. motor mounting height, engine trim angles and toe settings? Absolutely.

Boat makers, motors makers and dealers don't have the time or money to be doing this. More than likely 99% of the owners don't care to maximize performance. Particularly if time and money is required.
Old 08-29-2020, 07:56 AM
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Sad but true. There a many boat manufacturers that are just lazy when it comes to propping and send all boats out with a standard three blade that will perhaps reach the max RPM range and call it a day. I have owned several boats where I have ran 5-10 props to get a wealth of knowledge about performance of a hull, you would think the manufacture would like to do the same.
Old 08-29-2020, 09:11 AM
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Default Multi engine alighnment ....

all this is interesting .....we can not play with alignment on our rig .....two sea star slave cylinders on 60" centers,no tie bar, requires an equalizer valve.....
tilt motors up ...turn all the way left or right ....open valve ....wait 5 seconds...close valve ...motors are aligned




Old 08-29-2020, 09:14 AM
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More than likely 99% of the owners don't care to maximize performance. Particularly if time and money is required.[/QUOTE]


You nailed it................most boats we see in our shop are over propped and owners do not care
Old 08-29-2020, 11:08 AM
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Here are two pictures running 3500 RPM 27 MPH engines as close to parallel as the bottomed out tie bar would allow (about 1/4" toe out).


Last edited by Unevensteven; 08-30-2020 at 05:58 AM.

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