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View Full Version : Boat needed a lot more throttle to maintain RPM's & also seemed to hesitate



trayson
07-06-2016, 07:05 PM
I have had it happen twice where the boat is running fine. I am motoring back doing 25+ MPH with the RPMís around 3500. I have the wakeplate all the way down. The water isnít all that smooth, but certainly not whitecaps.

I come up on another boat and decide I want to pass them, so I give it more throttle and pull the wakeplate all the way up (because I know Iíll get more speed by reducing the drag of the wakeplate in the water). Just after that, I find that Iím having to give the boat a LOT more throttle to maintain the same RPMís and it feels like the boat is surging or hesitating enough to just be perceptible. This also seemed to happen just after hitting some waves after raising the wakeplate (making the boat bounce a bit on the waves).

Now, this has happened twice. So it could totally be a coincidence that after raising the wakeplate and giving it more throttle in not completely smooth water that the boat feels like itís starving a little and needs way more throttle to keep its RPMís. But Iíll throw it out there to see if anyone has some insight.

After throttling down and pausing for a sec, the boat operated normally from there on.

rdlangston13
07-06-2016, 07:30 PM
If you raise the wakeplate all the way up and go full throttle it can cause it to porpoise on you. I don't think that wake plate all the way up yields the most speed, it just allows yous ass to sink down deeper and generate more drag. You may want to drop the wake plate all the down and go say 5,000 rpms and check your speed, then move the wake plate 1/4 a time without coming off throttle and see if it speeds up as you raise it or slows down or if there is a sweet spot.

sivs1
07-06-2016, 08:23 PM
How much ballast is still on the boat? I had that issue a couple times after a surf session and bags are still 50% or so.

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kaneboats
07-07-2016, 10:56 AM
You'll likely find that at higher speeds if you raise the plate and thus the bow a little bit you will get more of the hull out of the water and pick up a few MPH. If you go too far you will get more drag, porpoising, etc.

trayson
07-07-2016, 11:29 AM
How much ballast is still on the boat? I had that issue a couple times after a surf session and bags are still 50% or so.

Sent from my SM-G900V using Tapatalk

I might have had a little left over, like an inch or two that didn't want to suck out of the bags, but not anything that would make a difference (especially since I wasn't going THAT much faster than I'd pull a wakeboarder/skier at).

trayson
07-07-2016, 11:38 AM
If you raise the wakeplate all the way up and go full throttle it can cause it to porpoise on you. I don't think that wake plate all the way up yields the most speed, it just allows yous ass to sink down deeper and generate more drag. You may want to drop the wake plate all the down and go say 5,000 rpms and check your speed, then move the wake plate 1/4 a time without coming off throttle and see if it speeds up as you raise it or slows down or if there is a sweet spot.


You'll likely find that at higher speeds if you raise the plate and thus the bow a little bit you will get more of the hull out of the water and pick up a few MPH. If you go too far you will get more drag, porpoising, etc.

Honestly the main part of my thread is the fact that the boat needed me to put the throttle WAYYYY farther down suddenly to maintain the same RPM's. Like 4 to 5" of throttle travel. And the boat was hesitating/surging. The engine wasn't performing as it should and behaved like it was fuel starved or something. That's what I'm trying to get insight on. I was just giving all the details of how/when it happened.

That said, we can address the tangent: I can tell you for a fact that my boat is faster with the wakeplate up than it is with the wakeplate down. I even confirmed it last night. I put the boat at 4000 RPM's on reasonably smooth water. The boat with the wakeplate down was going 30 to 30.5 MPH and when I raised the wakeplate up the boat would then go 32 to 33mph. You could even hear an audible difference of more splash with the wakeplate down as it brought more of the hull in contact with the water on the middle/sides of the boat.



So, all of that to say, I really don't care about how much speed I'm getting with the wakeplate up vs. down. It's more the fact that two times I changed the wakeplate at speed and immediately thereafter the boat started running poorly. Coincidence????? Maybe. But I'm more interested in trying to track down why my boat would need a TON more throttle to maintain the same RPM's. (and RPM's relative to throttle position shouldn't have that much variation)