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Put throttle into reverse while going fast

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Put throttle into reverse while going fast

Old 05-06-2019, 06:55 AM
  #41  
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Originally Posted by WillyC27 View Post
2 or 4 stroke?

4-stroke can swallow water thru the exhaust and hydro lock, hopefully not.
do you believe that to be true? or did i miss the sarcasm?
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Old 05-06-2019, 07:07 AM
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I have real data on this issue. About 7 years ago running down a rocky channel I spaced out but noticed that I was passing on the wrong side of a marker. I instinctively pulled the engine into reverse while doing about 3800 rpm. The F250 didn't stall, but it stuttered before actually running in reverse, which slowed me down and avoided a grounding. The engine ran fine, but since I was aware of the exhaust valve water ingestion issue and I wanted to check the lower unit, I ran back to the marina about 5 miles away. I changed the oil, which had 72 hr on it and sent in a sample for analysis as I usually do anyway. The results came back showing 60 ppm sodium, which is not a component of the Yamalube additive package and 98 ppm or iron. I normally see about 50 ppm iron per 100 hr and single digit sodium with this engine.

So change your oil as a previous poster suggested.
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Old 05-06-2019, 07:08 AM
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Originally Posted by mkalink View Post

You as with the others are wrong it will not reverse the direction and fill the motor with water. Even if for some reason it did reverse the pump won’t work in reverse.
What pump are you taking about? The water pump? How do you even think that's part of what everyone is discussing here? You should stop.
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Old 05-06-2019, 07:09 AM
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Originally Posted by krisinak View Post
do you believe that to be true? or did i miss the sarcasm?
Doesn't matter if you or anyone else believes it. A 4-stroke engine rotated backwards sucks in through the exhaust.
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Old 05-06-2019, 07:10 AM
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Two stroke pumps exhaust out the ports no matter which way it is spinning. Not so on a four stroke, spin that backwards and exhaust becomes the intake and it will suck up water from the prop exhaust toward the exhaust ports.

And it does happen in panic stops where shift goes into reverse while on plane.

Doubt it can happen? Go try it on a twin engine boat. Leave one engine off but in gear (use FWD for this test!!!!) and power up the other engine. If boat is capable of planing on one, with other prop stalled (not many can) watch the flywheel on the stalled engine. Get enough speed and stalled engine will begin to spin. A windmilling prop can apply a LOT of torque to the prop shaft. I have "bump started" a small outboard doing exactly this.
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Old 05-06-2019, 07:12 AM
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I just love these discussions Probably the most fun all day
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Old 05-06-2019, 07:21 AM
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Originally Posted by krisinak View Post
do you believe that to be true? or did i miss the sarcasm?

No sarcasm here.......I have a friend that did this with a fairly new Yamaha F225 to try to avoid collision with a whale that surfaced in front while at cruising speed, ended up a hydrolocked motor and a 35 mile tow in.
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Old 05-06-2019, 07:45 AM
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To the OP: this thread is dead, or rather, is a zombie. Happens every now and then here. Nothing to do w/ you.

If your motor is running, it is likely just fine. Check you oil level and motor on.

Your LU might not be your friend. Cheap insurance to change your LU lube, esp. if you can do that yourself. Unless you see chunks (fine dust does not count unless there is 1/8 cup of it), you are fine here too.
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Old 05-06-2019, 07:46 AM
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Originally Posted by WillyC27 View Post



No sarcasm here.......I have a friend that did this with a fairly new Yamaha F225 to try to avoid collision with a whale that surfaced in front while at cruising speed, ended up a hydrolocked motor and a 35 mile tow in.
So lesson learned, power up and fly over said whale? Or just pull the kill-switch?
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Old 05-06-2019, 08:26 AM
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Originally Posted by Texas 17 View Post


This is false. While I agree that if he had done this, it’s highly unlikely the motor would’ve run well for a while, this is absolutely possible. Putting it into reverse while going forward will stall the engine out, and then the prop geared for reverse while the boat is moving can spin the engine in the wrong direction turning it into a pump up the exhaust and into the motor.
It is not possible get over it.
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Old 05-06-2019, 08:52 AM
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I think some are forgetting that the prop spinning the motor is that the prop is at the back end of the torque multiplication process between the motor and the prop. Sort of like trying to push start a car in 6th gear instead of first.
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Old 05-06-2019, 09:01 AM
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Originally Posted by mkalink View Post

It is not possible get over it.
Lol. Care to explain why? Anyone can just say crap on the internet. Tell the people who had it happen to them why it couldn't happen.
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Old 05-06-2019, 09:02 AM
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Originally Posted by RIDE2GETHER View Post
I think some are forgetting that the prop spinning the motor is that the prop is at the back end of the torque multiplication process between the motor and the prop. Sort of like trying to push start a car in 6th gear instead of first.
This would work fine if you were already going 50 mph, like is essentially the situation here.
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Old 05-06-2019, 09:39 AM
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Originally Posted by Kr_1315 View Post
The "pump" is the engine. In reverse, the exhaust becomes the intake.
A four stroke yes,A two stroke no.
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Old 05-06-2019, 09:48 AM
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BAck in the day, we roll started our cars in second gear. 1st was too much compression. we were too broke to go buy a $35 starter back in the day until payday LO(L
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Old 05-06-2019, 09:50 AM
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Will the newer fly-by-wire digital controls even let you go into reverse at speed? I've bumped the super sensitive Suzuki digital throttles into reverse a couple of times by mistake and they just shutdown. Reverse didn't engage at all.
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Old 05-06-2019, 09:53 AM
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Originally Posted by mitchell master View Post
A four stroke yes,A two stroke no.
You are correct.
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Old 05-06-2019, 09:57 AM
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Either way, that airplane on that treadmill is going to take off.
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Old 05-06-2019, 10:04 AM
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Originally Posted by Bucklene View Post
Will the newer fly-by-wire digital controls even let you go into reverse at speed? I've bumped the super sensitive Suzuki digital throttles into reverse a couple of times by mistake and they just shutdown. Reverse didn't engage at all.
Some will.
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Old 05-06-2019, 10:06 AM
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Originally Posted by Texas 17 View Post
Lol. Care to explain why? Anyone can just say crap on the internet. Tell the people who had it happen to them why it couldn't happen.
And they do. All too much. Too often. Here on THT anyway. Worst boating site I have ever come across for crap information.

This is like the anti-hydrofoil crowd telling the pro-hydrofoil crowd that they can't, don't and won't work. When they do. For the pro users anyway.
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