What happened to my motor???

[kaydano]

I was doing a quick stop from full speed to get a better feel for the distance it would take my boat to stop. After letting dropping the throttle quickly, I immediately put it in reverse, but very gently, and gave it just a LITTLE gas in reverse. Again, I didn't slam it into reverse, it was gentle. I was still going forward at a pretty good clip (say 20 mph) when I put it in reverse. Instantly the motor alarm went off (continuous tone) and the motor shut itself down. I couldn't get it restarted, so after about a minute, I threw out an anchor due to the wind. I then tried the starter (starter turned, but no hits on any cylinders) and after a couple minutes, it started up and ran fine after that.

Anyone know what happened???

 

[hapehour]

I was doing a quick stop from full speed to get a better feel for the distance it would take my boat to stop. After letting dropping the throttle quickly, I immediately put it in reverse, but very gently, and gave it just a LITTLE gas in reverse. Again, I didn't slam it into reverse, it was gentle. I was still going forward at a pretty good clip (say 20 mph) when I put it in reverse. Instantly the motor alarm went off (continuous tone) and the motor shut itself down. I couldn't get it restarted, so after about a minute, I threw out an anchor due to the wind. I then tried the starter (starter turned, but no hits on any cylinders) and after a couple minutes, it started up and ran fine after that.

Anyone know what happened???

I have a good guess. The water alarm on the motor. It has a float in it. The yamahas ,if it is one has a water in the fuel alarm. If you jolted it it may have set the alarm off. A continuous tone is water in the fuel,a beeping alarm is low oil pressure or overheat.It will automatically drop the rpms down to 2000 to save the motor so you can get back to shore. The water alarm tone is only in neutral i believe. Hope this helps. HAPEHOUR

 

[kaydano]

I have a new (2011) Mercury 4-stroke. I don't think there's water in the fuel as it has never run rough (I know you are not saying I have water in the fuel, just stating this), and there was no perceivable "jolt" although shifting into reverse could have done that.

What was happening is the prop was certainly spinning in forward rotation fast (20+ mph) and then I put it in reverse. That could have been a jolt...

 

[StevL]

What was happening is the prop was certainly spinning in forward rotation fast (20+ mph) and then I put it in reverse.

Not the best thing for the gears! Glad it started and you have no problems now, I don't think I would try that again

Steve

 

[kaydano]

Yeah, hindsight...

I didn't think it through at the time. I was out alone, practicing very slow "tight-quarters" maneuvering out in the middle of the lake with a noodle that I was pretending was another boat or dock. Once I got tired of that, and was going full throttle, and since no one else was in the boat to get thrown around, the thought came to mind "I wonder how fast this thing could stop if I ever needed to" and so, yeah, I won't be doing that again. Even in an emergency, this is not something you want to do if the result is total loss of engine power. So, that was a lesson. Cutting throttle and turning hard is about all you can do, so that you still have maneuvering power in the seconds that follow an emergency. One stupid thing usually follows another, so having power if you need it is good. And in my case, I need all the help I can get.

Maybe there is a shock sensor or something that caused the shut-down. The owner's manual is pretty vague on what triggers alarms. Critical alarms either shut the motor off or put it in "limp home" mode. Non-critical alarms just beep the alarm. The only help the manual gave was take it in for service. Really??? It did say shifting into neutral and/or shutting down clears the fault (if it's not a permanent fault). The motor turned over right away afterwards, but it would not fire up for several minutes. Acted like it would if it was out of fuel. Then all of a sudden it started up and no problems the rest of the morning.

 

[Remediation]

My thought is to talk to Mercury. If I blow the gears out in an emergency stop I would understand but to have the motor die is not acceptable. The only brake I have on a boat is reverse. If the computer controls have so dumb things down to save the motor, people will get hurt. Nothing will work as good as our old runabout with a Berkley Jet that went from 50 to 0 at full power, but we are not running around with jet drives on our toons. I look forward to Mercury's response to your practice for a real world situation.

 

[Bigtop]

Your not fooling anyone, your just trying to Blow your 115 up so you will have a GOOD reason to upgrade to the 150. LOL. Just kidding. I am surprised it didn't break some teeth off of a gear. That's kind of like throwing your car in reverse going 20 mph. I can only imagine the jolt that was i have had to throw mine in reverse while moving very slow (not 20 mph) and evn then, it was a pretty good jolt.

 

[spinzone]

Your not fooling anyone, your just trying to Blow your 115 up so you will have a GOOD reason to upgrade to the 150. LOL. Just kidding.

That was the first thought I had too! Smart thinking my man.

 

[kaydano]

Your not fooling anyone, your just trying to Blow your 115 up so you will have a GOOD reason to upgrade to the 150. LOL. Just kidding. I am surprised it didn't break some teeth off of a gear. That's kind of like throwing your car in reverse going 20 mph. I can only imagine the jolt that was i have had to throw mine in reverse while moving very slow (not 20 mph) and evn then, it was a pretty good jolt.

THAT is hilarious! Certainly would be the upside...

Yeah, it was a stupid thing to do in hindsight. Hopefully this thread keeps someone else from doing it. We took it out today, and had no problems. I think I dodged a bullet.

 

[dmctruby]

I have the 115 HP Merc 4 stroke. It will alarm and shut down when doing hard circles (as in towing a tube in a max turn/ tight circle to give the tube rider added momentum). That has happened 3 times, I don't do that anymore . I presumed prop wash or strain leading to overheat had shut it down. It started right up again. My engine is also very sensitive to water flow. Excuse the terminology but the "stream force" of the water pump is not very good on my engine, and any time I am in weeds it will tend to alarm the motor into shutdown mode (again I presume it's sensing not enough water flow/ presssure....or the engine is getting hot from the lack of water circulation). I don't spend any time moving slow through weedy areas now.

At more then 20 mph the motor always runs great, no issues not matter what the conditions. I need to listed to the code sequence if I have another weedy water or slow moving shut down. I know in the manual the pattern of beeps tells you what type of issue shut the motor down. I can tell you it's never been a water in the fuel issue. I had the chance to see that first hand when my brother picked up his new benny just weeks from mine. We were using my trailer to get his boat home. It ran poorly, misfired, erratic idle at low idle and would shut down, higher speeds all was fine. He got a bad batch of fuel from the marina at delivery, water was his stalling/shutdown issue.

I also swamped the rear of the boat pretty bad this weekend. Kids were tubing and feel off. I am on a busy lake and was in a hurry to get turned around to pick them up. I hadn't noticed the tube had flipped when they were bounced off, turning around at full throttle to get them the tube submerged bringing the boat to a near full hault from 20 mph. The stern dropped low into the water and a water wave went over the engine, the stern took a healthy (or not so healthy) submerge. No issues however, motor never missed a beat, and thankfully the ski tow pole, mount, transom and all other things at the stern were not damaged. I expected a bent ski pole or stalled engine, but was lucky. A little sun to dry the carpets was all that was needed.