Both engines killed while shifting

chicago280da

New Member
Jun 15, 2007
5
Chicago, IL
Hi all,

Last evening I was manuevering through the harbor at slow speed (both engines at around 800 rpm) and using the twin screws on my 280DA to position for my slip when both engines suddenly died on me. At the time it was pretty windy and I was heading toward an obstacle, so you can imagine I was about to crap my pants. Fortunately, I was able to restart them in time...but the thought of this happening again scares the heck out of me.

A few pieces of information. This is a brand new (~15 hours of use) 2007 280DA. I was out on the Lake for about an hour prior to this and ran the engines at a variety of speeds (between 1000 and 3500 rpm, mostly toward the latter). I was using the twin screws (port forward/starboard reverse and vice versa, alternating them to adjust as I approached the slip) to maneuver at the time that the engines died in the harbor. My battery gauges on both engines seemed to be around 13-14V. One final piece of information is that I am usually on a mooring can (the slip was being used transiently for the weekend), so the only time the batteries charge is by the alternator when out cruising...however I stress the battery gauges seemed to read in a fine range and I had no problem starting initially or any other time.

I talked to a technician today and he said that when shifting there is a micro-switch used in bringing the props back into neutral and then oppositie gear. If the battery is just a little low, sometimes this causes an engine to die while shifting, since it relies on the electrical system for a brief period when shifting. Does this sound like what was going on? I am surprised that this could happen to both engines simultaneously (I may have been shifting both at the time, but still...).

When shifting from forward to reverse (or vice versa) is there a minimum amount of time that you need to stay in neutral? Was it possible I was shifting from forward to reverse too quickly? Does it sound like something more serious was going on?

Any help would be greatly appreciated! I am a total beginner at boating so if it sounds like I may have been doing something stupid while maneuvering that caused one or both engines to get killed, please let me know that as well.

:smt100

Thanks,
Mike
 
Please take the time to give us the engine and drive specifics in a signature line...........I'm guessing at location and boat from your screen name.

Not knowing the drive type for sure, here is a guess at what is happening so maybe you can understand the process.

Larger outdrives have big torque transmitted to the lower unit and reverse gears. Shifting into and out of gear while the motor is running causes the shift dog or gear to slam into the opposite direction when it engages. Obviously, you can't turn off the engines to shift gears so Mercruiser designed a shift interrupter switch into the gear shifting mechanism. It is a the microswitch your techniciam mentioned. It momentarily grounds the ignition and for all practical purposes kills the engine when you shift gear. That removes the torque from the shift dof or gears and allows them to slip into the opposite rotation without damage.

Your technician's explanation is entirely plausible, although I don't know why you would have low voltage in a new boat with fresh batteries unless the problem occurred immediately right after cranking.

I have always paused in neutral when shifting outdrives....or any other marine transmission for that matter. It gives the rotating parts time to slow down or stop moving before being asked to turn in the oppopsite direction and would be easier on the gearing.

It's a new boat under warranty, so go boating and have fun with it. What would concern me is if you can replicate the problem or if it occurs on a more frequent basis.
 
Thanks Frank.

Do you need any other information than what I put in my follow up post (and is now in my signature)?

I understand that it is best to leave the engines in neutral for a few seconds when shifting between forward and reverse to minimize stress on the drives/engine, but would not doing this cause the engines to conk out?
 
Would failing to leave the shfter in neutral a few seconds cause the motor to die?......No, it should not, if you have adequate voltage to and if the shift interrupter switches are properly adjusted.

You have a new boat under full warranty so I know Mercruiser is going to have to do their own diagnostics, but I also suspect your problem may be more likely the adjustment of the switches rather than low voltage on a brand new boat with brand new batteries that had just been run.

In shifting an outdrive, you will find it easier on the drive to shift smartly to neutral then smartly into gear rather than just slowly easing them out of and into gear. I wouldn't think you need to leave the drive in neutral a "few seconds".......shift smartly to neutral then hesitate in neutral (1 sec.?) then into gear.

And, your signature is fine........We've been getting a number of new members who, I guess for security concerns, fail to provide us with their location, boat type and the type power/drive they have. We are not here to stalk anyone, but there are some of us who are hard core boaters who do this forum stuff to help others and to stay active with boating when we are not using our own boats. Location tells us if you winterize and haul out for the winter and if you boat in salt or fresh water....model and year lets us give you precise answers for your situation and the engine and drive type lets us know if the boat is inboard or has out drives and, if so, what type. That means you get more accurate and precise answers to your questions in a more timely manner than if we have to ask you for the information. And, honestly, when other things are pressing, sometimes I don't have time to ask for the information needed and I choose not to respond rather then give generic answers.

Go use your boat and observe what is going on. If it still tried to shut down during shifting, get your dealer involved. Their priority is keeping buyers of 2007 model boats happy.
 
They shouldn't stall. You shouldn't have to pause in neutral and start counting 1 mississippi... Probably a bad switch or sensor on the motor.
 
I would not sweat this until you repeat the experience.

I had one engine die during shifting two weeks ago. I didn't give it a second thought (well. . .the docking became a touch more challenging. . .but this is why you go SLOW into docks). I am pretty sure that I have felt hesitation from one or the other engine during other attempts. My boat is a '97

Considering that I shift a large number of times every time I dock -> I don't think I have a problem.

I definately like to "pause" in neutral for a few moments before switching forward to reverse. My Alpha's will occassionally bark if I am too much in a hurry. Note that if things are going well. . that should not be a problem. If you *quickly* going from forward to reverse, that problem means you are moving too fast, and overcorrecting.
 

Forum statistics

Threads
112,942
Messages
1,422,701
Members
60,927
Latest member
Jaguar65
Back
Top