Supra 2015 SA400

[mor3naz0]

Hi All,
My Indmar 400 tops out at 4000rpm. All the specs I’ve read mentions maximum torque is at 5,400rpm.
I’ve only owned the boat for 12month and I know wake boats arn’t designed for speed, but I’m wondering if I’m missing out on power or possibly throttle cable adjustment to allow for WOT.

Any thoughts or experiences??

Thanks


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[Stazi]

Hi All,
My Indmar 400 tops out at 4000rpm. All the specs I’ve read mentions maximum torque is at 5,400rpm.
I’ve only owned the boat for 12month and I know wake boats arn’t designed for speed, but I’m wondering if I’m missing out on power or possibly throttle cable adjustment to allow for WOT.

Any thoughts or experiences??

Thanks


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4000rpm exactly, or somewhere around there?

If so it could be the ECM is limiting the engine to 4000rpm due to an out of spec condition it is seeing. Do you have a check engine light?

If it’s around that and not exactly that speed, you might have a prop on with too much pitch. What prop is on there? Get the part number and/or specs of the back of the hub.


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[TXSurf4]

Hi All,
My Indmar 400 tops out at 4000rpm. All the specs I’ve read mentions maximum torque is at 5,400rpm.
I’ve only owned the boat for 12month and I know wake boats arn’t designed for speed, but I’m wondering if I’m missing out on power or possibly throttle cable adjustment to allow for WOT.

Any thoughts or experiences??

Thanks


Sent from my iPhone using Tapatalk

I believe that the Maximum Torque with the Indmar Raptor 400 is achieved between 2,500 & 3,500 RPM. The WOT RPM is supposed to be between 5,000 & 5,400 RPM. I have to agree with Stazi if it is holding exactly 4,000 RPM might be an engine problem but other wise and maybe more likely it is a proping issue.

[mor3naz0]

Thanks boys.
I’ll check the RPM plus prop over the weekend and reply back.

I am a little confused though. If it just a “prop” specification and not the ECU telling it to stop at 4K why wouldn’t the engine rev still rev to 5400?

Does the prop create so much resistance/drag that the engine can’t reach that RPM?

I guess I’m drawing similarities to a car with different sized wheels. Engine still reaches same RPM but different speeds for different sized wheels.



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[Stazi]

You can’t directly compare it to a car as the load on the car is not constant, like it is on a boat. You cannot coast in a boat there is always load on the engine when moving forward. Think of it more like Top Speed in a car. So depending on what gear you are in you will reach a different top speed. In a boat the pitch of the prop dictates how much the engine can rev depending on the load on the engine which is directly related to the pitch of the prop.

If you had a prop with no pitch so it was basically a disk, the engine would rip all the way to redline and bounce off the rev limiter, but you wouldn’t move. Now think about it if you had a prop with a pitch that was let’s say 45°, so it’s pretty aggressive. The power of the engine can only turn the prop so fast and it will not reach redline as it will never be able to generate enough power to get there.


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[kaneboats]

That is a dang good explanation right there. You should also mention the elevation where you are running as it can affect things as well.

[larry_arizona]

Also how much ballast is in the boat.


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[TXSurf4]

You canÂ’t directly compare it to a car as the load on the car is not constant, like it is on a boat. You cannot coast in a boat there is always load on the engine when moving forward. Think of it more like Top Speed in a car. So depending on what gear you are in you will reach a different top speed. In a boat the pitch of the prop dictates how much the engine can rev depending on the load on the engine which is directly related to the pitch of the prop.

If you had a prop with no pitch so it was basically a disk, the engine would rip all the way to redline and bounce off the rev limiter, but you wouldn’t move. Now think about it if you had a prop with a pitch that was let’s say 45°, so it’s pretty aggressive. The power of the engine can only turn the prop so fast and it will not reach redline as it will never be able to generate enough power to get there.


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Good explanation right there ^^

Props can affect a lot about how a boat acts and performs.

[mor3naz0]

4000rpm exactly, or somewhere around there?

If so it could be the ECM is limiting the engine to 4000rpm due to an out of spec condition it is seeing. Do you have a check engine light?

If it’s around that and not exactly that speed, you might have a prop on with too much pitch. What prop is on there? Get the part number and/or specs of the back of the hub.


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Hi,
Have only just gotten time to get to the shed where the boat is kept. I’ve taken some pics of the prop, it’s a 1235.
What type of prop is this?
https://uploads.tapatalk-cdn.com/20190217/c895c7fc9b3901c88a0180636e1143ba.jpghttps://uploads.tapatalk-cdn.com/20190217/e70fe04cfd7bfa65267b96df1495cb16.jpg


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[Stazi]

That’s the standard wakeboard prop. Your boat should not ever have an issue with it. Sounds like something else in the engine management system is limiting the max rpms.


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[mor3naz0]

That’s the standard wakeboard prop. Your boat should not ever have an issue with it. Sounds like something else in the engine management system is limiting the max rpms.


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Ok thanks.
That gives me some direction.


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[Lisajpitts]

seems very complicated issue, standard wake-board prop. limiting the rpms.