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Old 08-12-2018, 09:24 AM   #1
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Default 2800 7.4L/Bravo3 - shifter sticking/motor free revving under load

While out on the lake earlier this week, I ran into a weird situation with our 2800. After we'd been out for a while, stopped for a while, turned the boat back on, and went for another leg, when I went to WOT to hop on plane, it started revving up and then free revved to the rev limiter as if it were disconnected from the prop. I tried a few more times and got the same result, but idling around or going at 7 kts around the lake was just fine. I noticed the shifter was a bit stickier than usual as well. I turned the boat off, moved the shifter back and forth from WOT forward to WOT backward several times, pressed the neutral button on the sihfter a few times while doing some more back/forth movements, and then when I turned the boat back on, everything worked fine.

I'm concerned something is going bad that is going to actually strand me at some point. Is this some predictable issue, or likely a one-off magic alignment issue?
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Old 08-12-2018, 10:04 AM   #2
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Default 2800 7.4L/Bravo3 - shifter sticking/motor free revving under load

Sounds like a spun hub in the prop. Had that happen to me last year. Would idle fine and even when it sat a bit it seemed to spin again, but I had to get the hub replaced. I had a greasy/oily slick behind my boat when that happened. Otherwise, sounds like worn clutch issues in the drive...
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Old 08-12-2018, 11:26 AM   #3
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I donít believe Bravo 3 has break away hubs. The coupler can spin and cause this issue. A Bravo should not be shifted in and out of gear with the engine off, cone clutch engagement requires the shaft to be turning.

When the rpms kicked up did the boat speed slow down. When you said everything worked fine do you mean you could get on plane and run at 3000 rpm of greater? If so I doubt itís the coupler. I would then look at cable adjustment and clutch linkage.
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Old 08-12-2018, 07:42 PM   #4
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When the rpms kicked up, the boat slowed down -- it was definitely not driving the prop, or at least the prop wasn't providing thrust. "everything working fine" was that we were able to plane home after that just fine -- 3900 rpms giving us 24-25kt cruise.

The only other question is that we were in a shallow area with a lot of weeds right before that, so I'm wondering if we had some **** wrapped around the prop that took some time to fall off, and we were just cavitating a munged-up prop at WOT, but the timing is coincidental...
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Old 08-12-2018, 10:05 PM   #5
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We have a lot of sea grass on the Chesapeake and if it get wrapped around the drive I cannot plane. After being in a shallow area I stop the boat and gun it in reverse to clear the drive.
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Old 08-12-2018, 11:48 PM   #6
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My coupler went out a few years ago while I was on the lake. Just so happened I was in a marina when it went out. It was doing some of the same things as yours. Once it goes the shaft will just spin inside the coupler.
I replaced it my self but it was a lot of work. Outdrive off, engine lifted, realignment, new coupler, replaced all the boots and upper u-joint on the drive. With the engine loose its a good time to inspect the Y pipe and replace swivel shaft and seal.
B.O.A.T. :-)
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