115 merc shuts down in rough water

[cdkeim]

Just had a question to see if it rings a bell with anyone.

My 2011 merc 115 4 stroke has recently started to shut off when I run in rougher water. it is good upto about 7-8mph but as soon as I go faster and the boat starts to bounce more the engine turns off. Starts again just fine, and runs fine otherwise. any thoughts? thank you!

[mooseknuckle]

Bit of a head scratcher, however I had a friend who was having the same issues. Turned out to be a lose wire on the kill switch. Long shot but worth a look.

[cdkeim]

Didn't think of that. Definitely worth looking at. thank you.

[RavYak]

Yeah check all your electrical, could be a loose are broken wire somewhere.

Could be something related to fuel sloshing as well but would likely only happen with a near empty tank and then would take a little more effort to get it started.

Those are the only things I can think of as movement shouldn't affect any of the other motor operations.

[harrydude]

Could be a loose fitting as well

[Kokanee9]

My first thought was water mixed in the gas. Easy starting rules that out.

Electrical makes much more sense. Start right at the battery connection and go from there.

Good luck.

[Hunting Guy]

Check the fuel line, it could be collapsing and cutting off fuel supply. Easy and cheap to replace from the tank through to the motor.

[cdkeim]

thank you for all the replies. I will work through them and see if I can figure it out.

[stusilver]

Originally Posted by cdkeim

Just had a question to see if it rings a bell with anyone.

My 2011 merc 115 4 stroke has recently started to shut off when I run in rougher water. it is good upto about 7-8mph but as soon as I go faster and the boat starts to bounce more the engine turns off. Starts again just fine, and runs fine otherwise. any thoughts? thank you!

I had the same issue with a 50 hp merc, scratched my head for about a week or so. Check the main fuse connection, they are notorious for breaking a wire internally, they will make partial contact then in rough water fail then be good again. You can check with an simple ohm meter (check the fuse first) then disconnect the quick coupling for the holder and ohm test. Try bending the wire when ohming the wires out. It's a $5 fix and a bit of time. Good luck

[Kokanee9]

Originally Posted by stusilver

I had the same issue with a 50 hp merc, scratched my head for about a week or so. Check the main fuse connection, they are notorious for breaking a wire internally, they will make partial contact then in rough water fail then be good again. You can check with an simple ohm meter (check the fuse first) then disconnect the quick coupling for the holder and ohm test. Try bending the wire when ohming the wires out. It's a $5 fix and a bit of time. Good luck

Excellent suggestion.

If this happens to anyone out on the water, most motors have a spare fuse inside the cover somewhere, or right beside the actual fuse itself, plugged into a dummy slot.

[bsmitty27]

Exact same thing happened to me last week in 65 merc. Wire split mde contact when bounced around or got wet. Shut off hard not like a fuel problem.
Good luck

[hiddenwalleye]

Just a thought, I have a 115 Yamaha, same thing, goes about 9 mph then bogs down, but starts and idle's good.............Took it in and it was the Injectors, they had to be taken out and given a solid cleaning, $ 700 to fix......Hope this might help!



Tight Lines



HW

[Off in the Bushes]

Check the oil level, (some motor have a low oil level kill switch) might be bouncing just enough to uncover the switch.

[BobNewton]

How does it die?

Like you turned the key off. (immediate shutdown) or does it struggle and stall?

Will help determine if it's a fuel issue or wiring or oil level as was mentioned.

[Shmag]

I leaning towards a broken/loose wire as well. Do you hear a series of warning alarms before hand. I believe there is one for low oil level.

My 08 opti, they have a computer port on it to plug a laptop into and can run a full history of the motor, just like a vehicle motor scan now. Not sure if anything would show up why its dying if no alarms are coming up....but who knows it might be picking something up to point you in the right direction...a shut down or loose wire can be coming from any where...I imagine it could be a nightmare to track down...

[CBintheNorth]

The fact that speed is involved (rpm), I would say you're looking at a fuel problem. Electrical problems aren't dependant on acceleration.
I would guess cracked fuel line but sounds too new for that.
I'll be following this thread as I'm curious to see what it is.
Good luck with your fix.

[lannie]

Originally Posted by CBintheNorth

The fact that speed is involved (rpm), I would say you're looking at a fuel problem. Electrical problems aren't dependant on acceleration.
I would guess cracked fuel line but sounds too new for that.
I'll be following this thread as I'm curious to see what it is.
Good luck with your fix.

I am curious myself but he did mention that it is rough water that brings the problem not just speed. With that info I infer he does not have the problem accelerating to full speed in smoother water. Sounds like it is a electrically induced problem.

[Ned]

Had that problem with my 90 merc this spring. Changed the fuel filters and no more issues

[lannie]

Originally Posted by Ned

Had that problem with my 90 merc this spring. Changed the fuel filters and no more issues

Only did it in rough water too?

[CBintheNorth]

Originally Posted by lannie

I am curious myself but he did mention that it is rough water that brings the problem not just speed. With that info I infer he does not have the problem accelerating to full speed in smoother water. Sounds like it is a electrically induced problem.

Sorry, you are correct. I misread that.
I thought it died in rough water OR at 7-8 mph.
If it only does it in rough water but never on calm water regardless of speed, I would also say Electrical.

[Ned]

yep, only in rough water. I had a full tank when it was giving me the problems. I changed the filters and have run the tank nearly empty since then with no troubles

[cdkeim]

Been out of town for abit so haven't had time to get into the motor yet but thanks for the replies. Called mercury and they were of little help, and even our local boat repair shop didn't have many ideas so I appreciate the input. And boat run fine right up to top speed in calm water, only shuts down in rough water. No prior warning beep, but it does beep after it shuts down. it starts right back up with no issues. I will check wires/fuses, maybe change fuel filters(couldn't hurt) and ensure oil level is up(all the easier stuff) and hope to find the culprit. Then wait for a windy day or hire a big heavy guy to jump on the front of the boat to test it out. Thanks again.

[CBintheNorth]

Originally Posted by cdkeim

Been out of town for abit so haven't had time to get into the motor yet but thanks for the replies. Called mercury and they were of little help, and even our local boat repair shop didn't have many ideas so I appreciate the input. And boat run fine right up to top speed in calm water, only shuts down in rough water. No prior warning beep, but it does beep after it shuts down. it starts right back up with no issues. I will check wires/fuses, maybe change fuel filters(couldn't hurt) and ensure oil level is up(all the easier stuff) and hope to find the culprit. Then wait for a windy day or hire a big heavy guy to jump on the front of the boat to test it out. Thanks again.

Try checking the manual about engine codes and monitor the beep when it dies. Sometimes it can tell you why it shut down (a series of beeps or one long one so many seconds long).
Also, I wonder if it could be a plate in the battery? They sometimes come loose and when tipped, arc against the next plate. I've heard of It in quad batteries.

[cdkeim]

An engine code would be great. I know its one longer beep but didn't think to try and time it.

[Walleye101]

My 2012 115 Merc has the same issue but also at idle speeds. 1 constant beep for 6 seconds say's a criticle engine problem is taking place and 6 beeps say's a problem is starting to occur. I had both beeps numerous times this past weekend and called Grady at Rainbow Marine. He said to bring it in and have it looked at. So i'll let you know what they find. Kind of scary when the engine stalls out and you have little kids in the boat with a big storm approaching.

[Walleye101]

The problem with my engine was the fuel supply pickup line in the tank.

[The Reel Deal]

This is an electrical issue if it just suddenly dies.

Won't be a battery since the battery's primary function in any system is to crank the starter motor. Once running the alternator does the rest outputting approx 14.5v to keep your battery charged and your electronics working. This also rules out the alternator, if it dies then the boat will run on the battery till it dies. Now you are stuck on the water and can't start the boat.

Best way to find your problem is get a set of muffs and run your engine in the driveway. Start wiggling wires under the dash and work your way back to the engine. Or gently tap on components with a rubber mallet imitating the shock these components endure in rough water.

[cdkeim]

thanks, I was kinda thinking along the same line. Try to recreate whatever it is shutting it down.