Merc Verado issues in rough water

Hoping one of you smart folks could help me diagnose a potential engine issue over the interweb.

Here’s the back story, I was up on LOTW this past weekend and it got a little breezy on us. We were heading from the river up to Garden Island area in the morning and things were a little rough. I have a lund 186 glass boat with a merc verado 175. We got about 4 miles out cruising along at about 3/4 throttle and the smartcraft gauge gave a loud beep and shut down the engine. Went to the back to check it out and a faint white smoke was coming out of the engine. I assumed it overheated. Waited a while, started it back up and the temp was normal and putted back to the dock. When we got to calmer water I opened it up and it ran just fine.

Later in the day we decided to fish Pine Island area. Engine started fine and seemed to run fine in calmer water. When we got out to some waves I noticed the trim # on the smartcraft gauge was jumping around. It didn’t deviate much but would jump around between 0.1 and 0.4 on the gauge while we were cruising. All of a sudden the same thing happened, a loud beep and the engine went to idle. This time I noticed the temp was fine, the water pump was spitting water out of the engine just fine, and it had nothing to do with overheating this time. I immediately got back on plane but at a lower speed and got to the spot we wanted to fish. No issues on the way back.

Well… what do you make of this?? This is the first time in this rough of water with this boat. Never have had an issue before but I’ve only had the boat since last Aug so not a ton of time in it. I’ve been in at least as rough of water maybe worse in previous aluminum boats and had no issues like this. Thoughts?

Does your motor have a check engine light? It may be possible to hook it up to a diagnostic tool to see what code it was throwing with it being a newer motor. If you find out the code you could work it backwards to find the cause.

That’s a good question. I don’t know? I’ll check when I get home.

Call your dealer. He likely has heard the symptom before, he will need to know for sure how many beeps and how long they were. Long beep, short beep.

It should have thrown a code, bring it in and have them run it.

How old is your impeller?

Was the prop cavitating and over-reving the motor?

Have you checked your oil level? If it’s too high there’s a chance the oil pressure was too high, especially bouncing in the waves??? Just a total guess

Any chance your ground is loose? Or a batter connection is loose. I’d also check under the cowling that all the nuts are tight that have a wire on them. Also check the fuses to make sure they are pushed all the way in. Any chance it’s loosing power and the beeping is the same beep as when you turn the boat on? I’d also check the kill switch. Seems like the rough water is causing some wire to bounce around.

Was your engine trimming itself up? Maybe a bad/loose trim switch slowly bumping it up in the rough water until it wasn’t sucking enough water?

label033 wrote:

We got about 4 miles out cruising along at about 3/4 throttle

label033 wrote:

When we got out to some waves I noticed the trim # on the smartcraft gauge was jumping around. It didn’t deviate much but would jump around between 0.1 and 0.4 on the gauge while we were cruising.

When running this rough water are you working the trim up and down? Are you working the throttle faster/slower?

I have a gut feeling you are just running the chop without adjusting to the constantly changing chop. I think you may be over trimmed at times and taking in air at the water intake. This will set off the overheat alarm (Constant beep) at times. Basically creating steam on the temp sensors. The newer Mercs will put the motor into limp mode when it trips this sensor. Turn key off and back on to reset. (Sounds like you did that.)

I would try running the motor at near full down trim next time you are in similar chop. Raise the bow by pushing more throttle rather than more trim. Find the sweet spot where your bow is up enough and your running temps are normal. For example, if you are set into a big plow, your motor will run on the high side of the temp range. The right mix of lift and run will be a nice smooth ride with no rear end prop blow out coming off bigger waves. This requires constant adjustments to the throttle and little up/down adjustments to the trim.

If you had a bad impeller/water pump. I’d expect you would also be setting off the over heat alarm in calm water or at idle, not just in chop.

-J.

Jon Jordan wrote:

<div class=”d4p-bbt-quote-title”>label033 wrote:</div>
We got about 4 miles out cruising along at about 3/4 throttle

<div class=”d4p-bbt-quote-title”>label033 wrote:</div>
When we got out to some waves I noticed the trim # on the smartcraft gauge was jumping around. It didn’t deviate much but would jump around between 0.1 and 0.4 on the gauge while we were cruising.

When running this rough water are you working the trim up and down? Are you working the throttle faster/slower?

You could be right, I was playing with throttle more than trim but I didn’t pay attention to where trim was at, I thought I had it all the way down.

I’ll try that next time. I am by no means a big water expert so thank you for the advice.

I brought the boat in to the dealer to have something else looked at so they were going to do a quick check on the motor too to make sure everything is fine. I don’t know enough about these engines to diagnose, even with your suggestions. Thanks for the replies though!

Not a Merc but my Suzuki does that every 100 hours as a oil change reminder. I have to pull the safety switch out 3 times to reset it. Maybe Merc has something similar?

If the motor checks out ok and the problem is rough water only, it may be motor height. Remember, the dealer sets these up for overall performance and top end in mind. A motor drop one hole may fix the issue long term. The trade off is usually 2 to 3 mph on the max speed.

I’ll trade 2-3 mph for this not happening again! We’ll see what the dealer says, hopefully soon.