Here we go again... Motor cuts out momentarily, long beep and keeps on truckin..

BellevilleMXZ

pop out your panel with the battery switch on it....quite a few of us have found loose wiring there

J3ff

Will do, and will clean all those connections. I'm paying more attention to the details now.  It has the problem at somewhere around 1100 rpm's, the beep happens and then without touching the throttle, it settles lower than 1100, more like 700/800  I noticed that twice today. Really REALLY odd there. 

Robs_232

It sounds like a bad electrical connection somewhere from key to engine. First I would find the main ground from battery to engine. Bad grounds can cause many electrical gremlins. Make sure paint or a loose connection isn't the issue. This is first step even if it sucks to get too. Then...

On the back of the engine there is a main wire harness connection. It looks like a rubber tube (boot) with a hose clamp on it. If you can't find it google Mercruiser engine wiring harness connection.

Loosen the hose clamp and pull connection apart. Use spray electrical contact cleaner, but read the cleaner directions to make sure it won't damage the rubber boot and plastic connectors. If there is a green looking corrosion moisture has entered the connection. You may need to use a small flat bladed precision screwdriver to clean both the male pins (mine has 10 male pins) and the female connections with the contact cleaner. Take the precision flat thin bladed screwdriver and slightly spread the male pins, as they are split in half.

 Then apply some dielectric grease to the male and female connections. I would also put some on the inside of the connection boot cover by applying on your finger and spreading it on the inside lip of the boot. That will help keep moisture out.

Rob

J3ff

Thanks Rob, your post reminded me that the day that this started happening I was down there reconnecting the smart craft "terminator" because my vessel view mobile wasn't working.  I went back down there, and disconnected, checked and wiped all the connections.. it's made 4 successful trips in since then. Not ready to declare victory..but hopefully that was/is the problem!  Will be picking up some DE grease tomorrow. 

Dream_Inn

@j3ff - you are overdue to have some trouble-free boating time!  Cheers to this problem being fixed!!

randy56

@J3ff Had an idea for ya, stay on your boat for two/three weeks, don't go home, to see if you really like a live aboard

J3ff

So I sent mercury an email over 4th of july weekend.. here's their response..

"Thank you for contacting MerCruiser regarding your engine serial number xxxxxx. The issue you describe sounds like it could be losing ignition back to the engine wake system (purple wire ignition power on circuit). This could be several items either caused by a faulty part or loose or poor connection. You could eliminate the entire helm harness by plugging in a Boat in the Box to the 10-pin helm harness connection at the engine. If problem goes away when running, this means issue is between the helm harness and the components at the helm. If issue stays with engine, then the issue is narrowed down to engine components or engine harness. Check all wire connects from battery to engine and out."

Hopefully as said above I caused this by messing with the "terminator" connection for the vessel view. It sounds likely based on their email diagnosis.. very impressed with mercruiser email support. 

Dream_Inn

J3ff, it's great to hear you've gotten some good info from merc.  I have found them to be very supportive of their products!  Good luck and yes, it sounds like a bad wiring connection could fix the problem.  I know someone that had a 342 and had an issue with the main connection from the boat harness to the engine harness.  They were known to come loose.

Willhound

Good info @J3ff. I was/am having the same issue, and as others have suggested it doesn't seem to be fuel as was confirmed last Saturday when I had a no-start at the marina. Was experiencing the cut out at speed like you were, and then the last few weeks, was getting difficult to start. After the no-start on Saturday, confirmed that not getting any spark. Working all week, so I have the mechanic at the marina looking at it today so that hopefully all sorted out by the weekend when we have a 3 day trip planned. He's going to check all the connections as above and also change out the ignition module in the distributor. Keeping my fingers crossed.

jme097

I would be crawling all over that engine compartment. Check all grounds and also for loose connections especially the wiring harness on the block

Willhound

Yep. Done. Mechanic tells me he did that as well as changing out the ignition module. Fixed the starting issue for sure, will head out on a run tomorrow and see if it fixed the intermittent cut-out.

J3ff

I just did a three hour run.... No problems 

69fastback

That's good news. What about the strange beep on engine cranking?

davidbrooks

@J3ff  They recommended for you to "eliminate the entire helm harness by plugging in a Boat in the Box to the 10-pin helm harness connection at the engine".  What is a boat in the box?

reneechris14

@davidbrooks a boat in the box is a self contained  portable helm. A key and a set of gauges.like in some of the videos when they run an engine out of the boat.

J3ff

Well since going down and messing with the yellow connector for the vessel view, I've had no more problems with the engine cutting out, but now VV mobile wont connect again. Not going to mess with it anymore I guess.. 

Willhound

At least you're running. My periodic cut out has changed into a genuine dead no start. Cranks like crazy but no spark. Trying to fix the cutting out at speed I changed the fuel filter, distributor and rotor and the ignition switch and the module in the distributor.  Was still suffering from intermittent hard starting so mechanic suggested changing spark plugs which I had him do yesterday. After 4 hours of pulling, checking and cleaning various connections he calls me to report he can't get it started. Even tried a different coil. Meeting him at the marina this morning and he's bringing his manual with wiring diagrams.......



 

Handymans342

Have you pulled apart the harness plug and checked for corrosion???

Willhound

He did a cursory check, but that's the plan for the coming week is to go over ALL of the harnesses. Bless the mechanic at our marina. He knew we had planned a weekend trip. We stayed over last night and as I was having my morning coffee he pulled up and brought his tool bag. About another 40 minutes of trying some different scenarios we narrowed it down to either a bad wire between the ignition and the coil or in the harness. It seems the voltage to the coil is dropping off. By running a jumper wire to supply direct voltage from battery to coil it started right up. He's rigged up a bypass with a toggle switch temporarily and it's working. Might salvage the rest of the weekend and he's going to tackle tracking down the bad wire/connection this week.

randy56

Hope, you have a weekend with out any breakdowns, it's frustrating. bad wire to coil not a bad repair, just finding it was a treasure hunt.

J3ff

Well after running for almost 8 hours with no problems, I decided to try vessel view mobile one more time and it worked!  The crazy thing is my tach is almost 600 rpm off at certain points, VVM is reporting 4000, tach is reporting 4600.. geezuz 

Handymans342

Was that at WOT? 

J3ff

no- after beating on her, I didn't want to do a WOT run.  I ran 2 hours in big waves yesterday... toilet lid broke off, multiple screws on the bimini backed out, little gel coat damage where the anchor chain hit the area around it.. lots of groaning from the outdrive and took a few over the bow, not like BIG over the bow, but enough to get the bow rails dripping..    

Today was a dream, flat calm the whole ride, went with the tide and only burned 1/2 the gas I thought I was going to.. will hope for weather just like that on the way home.. 

Willhound

@J3ff, happy to hear your trip is going well, and apologise for hijacking your thread.  We also had a successful 2 + hour run. The cut out came back, but at the mechanics suggestion I turned the switch on he installed to supply direct 12 v to the coil and the cut out stopped. Engine never ran so good! Next step this week is to figure out where in the ignition wiring the problem is and then the stutter should be gone for good.