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Charles, Marine Mechanic
Category: Boat
Satisfied Customers: 5128
Experience:  US Navy (Ret) Certified Mercury Marine Tech with over a decade of repair experience.
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Mercury 2015 1115 EFI, Engine turns over but will not start.

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Mercury 2015 1115 EFI, Engine turns over but will not start. Fully charged battery, new plugs just installed, gas exists small tire like valve afters high pressure fuel filter.
JA: Sometimes things that you think will be really complicated end up being easy to fix. The Marine Mechanic I'm going to connect you with knows all the tricks and shortcuts. Tell me a bit more about what's going on so the Marine Mechanic can help you best.
Customer: 115
JA: Is there anything else important you think the Marine Mechanic should know?
Customer: First time trying to start after sitting for 3 months.
Customer: replied 7 months ago.
All mini fuses on the two engine mounted fuse holders test good
Customer: replied 7 months ago.
When turning the key to the on position and then pressing down, the fuel pump runs for 5 seconds and then turns off.

H​ello my name is ***** ***** am I speaking with? I read what you wrote. Mercury outbaords are cataloged by serial number, can I get that number so I can see which version of the 115 you have? Next, are you able to check things like spark output and fuel pressure?

Customer: replied 7 months ago.
Hello Jason,
My Name is***** 115 EFI - SN 2B079093
I have an inline spark tester but have never used it with an outboard, can I disconnect a coil one at a time and use the inline spark tester between the coil and the spark plug under test, while leaving the other 3 connected normally? Also, I was going to pick up a cheap fuel injection pressure test kit from Harbor Freight to test with, would that work ok?Thanks,

H​I Chris. Lets start with the basics. Is the emergency stop switch clip in place?

Customer: replied 7 months ago.

I ​don't want to get your hopes up to high on this one. Being and EFI engine, if the problem is ultimately some sort of sensor issue, we are not going to find it without a scan tool. However, we can check some of the basic things. Are you willing to get a fuel pressure gauge, as well as an adjustable gap spark tester? Something like this, in this link - Also, do you have any starting fluid?

Customer: replied 7 months ago.
Understood, just wanted to check as many things as possible before having to take it in. I am definitely willing to purchase the items I need to test with. Here is a link to the Spark Tester I already have And here is another link to the Fuel Injection pump tester, which appears that it would fit. While I do not have starting fluid on hand I can easily pick some up. Can I use the tools that I already have?

Yes you can use those tools. On the spark, just unplug the coils, plug it into the spark tester, crank the engine over, and see if there is spark on the tester. Just do 1 at a time on those. On the fuel pressure, just hook that up to the Schrader valve, cycle the key from off to run 3 times, and then see what the pressure reads.

Customer: replied 7 months ago.
when I hook up the pressure tester to the schrader valve and turn the key from the off to run 3 times I get no pressure recorded, but if I turn the key to run and press down to prime I got around 40 psi. I also checked the spark on the very top plug and was unable to see anything. One more thing is that I hear nothing when I turn the key from off to run, but got several beeps when pressing the key down while in the run position.

but if I turn the key to run and press down to prime I got around 40 psi.​

​Okay that is not normal. Out of curiosity if you push the key down, and then hold it down and turn it to start at the same time, will the engine start or attempt to start?

Customer: replied 7 months ago.
No it just turns over the same is if I was not pushing in on it.

Do you have a volt meter so we can test the key switch itself?

Customer: replied 7 months ago.
I cannot do it right now as I have to go somewhere, but can definitely run through some tests later. I also picked up some starter fluid and have it available.

W​hen you get a chance pop the key switch out. Then hook you your meter to the purple wire on the back of the switch. Let me know if that wire shows 12V or not when the key is in the run position.

Customer: replied 7 months ago.
Just checked and when the key is in the run position I get 12v on the purple wire and 0v when the key is in the off position.

I'm actually about to log off for the evening, almost bed time for me, and we can pick this back up in the morning. But just to confirm, the fuel pumps come on when you push the key switch IN? Is that correct?

Customer: replied 7 months ago.
I verified that the pumps turn on, based on the associated sound, for approximately 5 seconds and then turn off.
Customer: replied 7 months ago.
have a good night, just let me know if you can think of anything else I can check.

G​ood morning. This key switch isn't working the way it is supposed to, and I'm confused by what you are witnessing. I just want to confirm. If you turn the key to RUN, you do not hear the fuel pumps kick on? However, if you push IN on the key switch, you hear the fuel pump run. Is that all correct?

Customer: replied 7 months ago.
Good Morning, I just double checked and when I turn the key to run, I hear nothing, when I turn the key to run and press it in I hear the fuel pump run.
PS - My boat is parked outside in my driveway and it looks like a big storm is heading my way. Probably only have about another 30- 60 mins to test things today.
Customer: replied 7 months ago.
Do you think it would be worth a try to bypass the kill switch?

If what you say is accurate then you either have a bad key switch or some kind of short circuit in the wiring harness. Pushing "IN" on the key switch should not do anything on your engine. The IN position is for older carbureted engines. They simply use the same key switches because they are universal. On your engine, the fuel pumps should come on when you turn the key to run. At this point you would replace the key switch, and if for some reason that doesn't fix it, then we have to hunt for a short circuit and try and find it.

Customer: replied 7 months ago.
ok, that makes sense. I will remove the key switch and order a replacement.

Let me know how you make out.

Customer: replied 7 months ago.
I just ordered a new switch that appears to match the one I removed, and it should arrive in a couple of days. I will install and let you know what happens when I get it.Starter Switch Ordered:,

Okay Chris let me know how you make out.

Customer: replied 7 months ago.
Hello Jason, I found the attached switch continuity test document online and the switch actually tests ok with a multimeter. I will go ahead and replace the switch when the new one arrives, but what would be the recommended next steps if replacing the switch does not fix the problem.

H​ere is kind of what I am having a hard time understanding. When you turn the key to run, this powers up the purple wire. The purple wire is what powers up the main power relay on the engine. The main power relay is what kicks on the fuel pumps. When you push the key IN, the key switch powers up the yellow with a black stripe wire. If this was a carbureted engine, that yellow/black would power up the choke. However, on the EFI engines, that yellow/black wire that comes off the key switch isn't attached to anything. It should be there just hanging off the back of the key switch, but not actually connected to anything. When you tell me that when you push your key switch IN and the fuel pumps come on. That tells me that the key switch is powering up the purple wire when you push the key IN, which it should not be doing.

Customer: replied 7 months ago.
Interesting, the yellow/black wire has a quick disconnect between the switch itself and the directly attached 6 position wire plug, but it was connected. When it stops raining I will try to see if I can figure out where it connects to under the console.
Customer: replied 7 months ago.
Just FYI - I am not the original owner of the boat, so I am not sure what the previous owner may have done.

Have you ever personally seen this engine start?

Customer: replied 7 months ago.
I have owned it for over a year now and it worked perfectly all last summer. This is the first problem I have had with it, but also the first time I have tried to start it after it sat idle over the winter. I put fuel stabilizer in it, filled it up and then ran it for a while before storage.

N​ot that this should matter all that much. But if you turn the key to run, and then push it in, does that yellow/black wire show power with the key pushed in?

Customer: replied 7 months ago.
the yellow/black only has power when key is in run position and pushed in. I traced the Purple wire from the start switch and it is spliced into three leads, one going to the speedometer, one going to what looks like a small buzzer and the last one going to a 12 pin connector. I also traced the yellow//black wire from the switch and it is going to a white wire on the same 12 pin connector.

A​t this point I have no idea why the fuel pumps are coming on when you push the key to start. The 2 electrical circuits (the choke circuit and the ignition circuit) are not even connected, so I have no idea why it's happening. I will opt out and leave your question open to the community.

Customer: replied 7 months ago.
one minor correction, the spliced purple wire actually goes to some other gauges and not the speedometer like I original stated, so when you turn the key to run the gauges (fuel level, tilt etc..) come on.

Hello, my name is***** you still require assistance on the engine?

Customer: replied 7 months ago.
if have you read the previous correspondence and think you can help.

Yes, what is the brand of your boat?

Can you unplug that yellow/black wire and see if the engines fuel pumps will run with the key turned to on?

Customer: replied 7 months ago.
My boat is 2014 Lowe Stinger 195DC. Unfortunately it is dark and raining so I can't try this right now, but as soon as I can I will test and let you know the results.

Great. I look forward to it.

When you get out to it, also look to the engine connector for the main harness. It is a large round connector. Unscrew it and disconnect it from the engine. Then give the boat side of the plug a slight wiggle or tug to see if the cable end will come off or stay. I have seen them come apart in the past.

Customer: replied 7 months ago.
OK, will do... Thanks for the additional ideas.

Your very welcome. Ill talk to you when it dries out some.

Customer: replied 7 months ago.
I had a few minutes are preformed the following tests.
1. Unplugged YEL/BLK wire from Ignition Switch - No change in turning key to run / Fuel pumps no longer come on when pushing in key.
2. Checked engine connector at the boat, based on your directions, and it appears to be OK.
3. Tested Neutral Start Safety switch - Tests OK (Open circuit when in gear / Closed circuit when in Neutral)
4. Tested Kill Switch - Tests OK ( Run = Open circuit / Off = Closed circuit)
5. Tested Fuel Pressure at Schrader valve - 0 PSI when cycling ignition switch from run to off several times / 50 PSI when in run and pressing in on key. Just wanted to verify that the fuel pumps were in fact, not coming on when the key was in run.Have to get back to work, but thought I would share what I was able to test out. While I thought the ignition switch tested OK with an ohm meter based on an online document I found, I do have a new one on order based on Jason's recommendation, as the old won was a little sticky anyway.

Has the connector between the engine and the boat come apart in the past? It is the large round connector on the right side of the engine. Disconnect it and make sure that all is still ok there.

Customer: replied 7 months ago.
That is what I did on test 2 listed above. I unscrewed the connector looked at all the pins and screwed it back on. I was unable to find anything wrong with it.
Customer: replied 7 months ago.
The connector between the boat and the engine has never come apart in the past.

Ok, does the fuel gauge read out when the key is just turned to on? Or does it only read when you push the key in?

Can you take that 12 pin connector apart in the dash, the white one you mentioned earlier, and see if any of it is melted?

Customer: replied 7 months ago.
Ok, it finally stopped raining here in St Louis.
When I turn the key on both the fuel gauge and the trim gauge respond. I checked both of the large white connectors under the console and there does not appear to be any damage to them.

Is the new key switch in yet?

Customer: replied 7 months ago.
No I did not want to change a bunch of things while testing since the old switch did test OK. I can do so if you think we should at this point.

I feel that since you already have it, might as well put it in and start eliminating things. All the tests are coming back as good, but there is something that is just not right.

Before you install the switch, try and get a look at the entire run of the harness between the key and the engine. Make sure that there are no breaks or chew marks in it. I have seen rodents tear up some over storage times.

Customer: replied 7 months ago.
OK, so I replaced the ignition switch and no change in symptoms.
When I turn the key ON the Fuel & Trim gauges come on but I do not hear the Main Relay click nor does the Fuel pump come on.
Since I have already verified that I get power to the purple wire from the ignition switch when I turn the key to run, Is there a test I can run closer to the motor, maybe at the Main Relay, to verify I am getting the correct power at that point when I turn the key on?

You can test the power to the relay. the 12V + is on the yellow or purple wire going to the relay. It is only there for the first few seconds after key up.

Did you look at the harness from the engine to the motor?

Have you seen this engine run?

Customer: replied 7 months ago.
ran perfectly last year, problem occurred when trying to start after winter storage.

Have you done anything to the batteries since it last ran?

do you have a piece of scrap wire, I have an idea for a test.

Customer: replied 7 months ago.
Main Relay Test
Key off
Red = 12v
R/W = 0v
R/P = 12v
Y/P = Fluctuating Voltage

do you have a helper to do the key on test?

Customer: replied 7 months ago.
batteries fully charged and even tried a second battery
Customer: replied 7 months ago.

Would be interesting to know.

Customer: replied 7 months ago.
I do have a helper
Customer: replied 7 months ago.
could that Fluctuating Voltage be due to a short in the wiring?

Yes it can, that is why I mentioned to check the harness from one end to the other.

Customer: replied 7 months ago.
when I disconnect the main round wiring connector, I still get the Fluctuating Voltage.

What does it get up to?

Can you take one of the trim relays and swap with this relay to see if the voltage stops?

Customer: replied 7 months ago.
I am checking the wiring while it is unplugged from the relay

That would be a back feed due to no ground to kill it from the ECU and the key switch.

Customer: replied 7 months ago.
OK, So what would be the next steps?
Customer: replied 7 months ago.
You mentioned a test using a scrap wire, what were you thinking.

For the wire, unplug the key switch at that 12 wire plug in the dash, then jump, using that scrap wire from the red to the purple and see if the pumps run on the engine.

Have you also looked at the harness from the helm to the engine?

Also, have you had anything installed or removed that would require part of the rear of the boat ro come up?

Customer: replied 7 months ago.
Not sure how to check the harness, most of it is inaccessible. I looked at both ends but could not find anything wrong. I will run the jump wire test and let you know the results.

There is that corner plate in the rear of the boat that can be taken up to give you a bit of a look. It will be screwed to the floor and possibly to the side as well. Using a phillips screwdriver to move the carpet around, you will find the screw heads.

Customer: replied 7 months ago.
Jumping the purple to red does nothing.
Customer: replied 7 months ago.
OK, I will see if I can get the corner plate of tomorrow and take a better look at the wiring.

Sounds good. The plate where the control box is mounted will come off too if needed.

If you have had anything installed, even a transducer, there is the possibility that a screw has gone thru the harness and that is causing this whole mess.

Customer: replied 7 months ago.
I did install a GPS module for my Lowrance and used a wire snake to get it through the side of the boat, but did use the boat a couple of times after that with no issues.

Look around the areas where you mounted that antenna, there may be an issue. As a test you could pull the mounting screws from it and see if the engine behaves correctly.

Customer: replied 7 months ago.
OK, so I just checked the wiring harness from the large white connector under the console back to the large round plug that plugs into the engine. I verified continuity from each end of every wire and even checked every other wire for any bleed over and the cable tested OK.

That is good news. But not really.

Customer: replied 7 months ago.
I would agree. Is there a sensor that could prevent the fuel pump from coming in when I turn the key on?

There are a couple. But pushing in the key should not over ride them. Question, is there a primer bulb in the fuel line?

Customer: replied 7 months ago.
I installed one after the engine would not start and I saw no fuel was getting to the fuel filters.

Ok, on the upper left side of the engine there is a green cap. Remove it and press in on the schreder valve inside there. It may help to follow that hose to where there is a quick connect, then press in on the red or blue tab on the connector and seperate the two hoses. What you are looking for is any fuel that may come out of this hose.

Customer: replied 7 months ago.
OK, so I removed the valve from the purge vent and then disconnected the hose from the bottom of the canister assembly vent and no fuel came out. There is also a small canister device to the left of the purge vent going to the air filter. Should air flow freely through that vent. When I blow into the purge vent and plug the hose going to the canister assembly it appears to be blocked going towards the air filter.

The canister is the vent purge valve. It is controlled by the ECU as to when it will open and close. Since you did not get any fuel from that hose, unplug the harness from that valve and try your key again.

Customer: replied 7 months ago.
It appears that we have made progress, but the boat will still not start. Now with the canister harness connected or not, when I turn on the key the fuel pump does eventually come on but cycles on and off multiple times and there is a lot of associated beeps with it. See the video here:

Ok, press on the schreder valve in the high pressure fuel line going to the injectors and see if you have pressure there.

Customer: replied 7 months ago.
50lbs when the fuel pump is cycling while the key is on

Does it seem to want to fire at all?

If not, pull one pf the plugs and see if they are wet

Customer: replied 7 months ago.
pulled top plug and it appears to be dry

Ok, plug in that sensor to stop the alarm and check those pumps again.

Customer: replied 7 months ago.
the sensor was plugged back in on the video I sent over

Is any sensor unplugged?b That code is for a sensor.

Customer: replied 7 months ago.
not that I am aware of

That would also include the coils.

Customer: replied 7 months ago.
Everything is connected and I get the same results. I baught a single adjustable ignition spark Gap tester. Can you walk me through how to verify we are getting a spark. can I just disconnect one coil and place the spark Gap tester inline between the coil and ground, while the other coils are connected as normal?

Yes you can do it that way. Make sure that the tester is plugged in firmly to the coil.

It is easiest to unplug the cils before taking them out.

Customer: replied 7 months ago.
the coil does not seem to clip onto the plug/tester but instead has a spring in it. Can I hold the coil against the tester and watch for spark while the other end is grounded. Please see attached picture and let me know if you think this is ok. Of course I will keep my hands away from the other end.

Yes, but set that gap to 7/16"

Customer: replied 7 months ago.
ok, so I checked for spark on the top 2 coils using with the use of a jump switch at the selinoid. I tried with the key on and off and see no spark.

Is the kill switch at the control box connected and on?

Customer: replied 7 months ago.
it is connected and in the run position

Try the spark with the large round 14 pin connector disconnected. You will need to jump the solenoid again.

Customer: replied 7 months ago.
same result and I also verified that ground I am using for the test is good

Still have that multimeter? If so, unplug the crank position sensor, and do a resistance test on it. It needs to be 330 Ohms.

Customer: replied 7 months ago.
but not sure where the crank position sensor is located

Under the plastic cover on the top of the engine. Pointed at the flywheel. It has two wires coming from it to a plug in.

Customer: replied 7 months ago.
it reads 314

It is good.

Customer: replied 7 months ago.
well I think I am going to wrap it up for tonight, but if you think of anything else please let me know and when i get back to it, I will let you with the results.

I think at this point it really may need to get into a Mercury shop and be connected to the computer so that the cause of the alarm can be determined.

Customer: replied 7 months ago.
Yeah, I was afraid that might be the case. There is a 3-4 week wait at the local shop so I was hoping we could figure it out. I really appreciate your help, If nothing else I learned quite a lot about my boat and engine.

I was hoping that we could get thru it as well. I hate to send them to the shop at this point, but we have done about everything that can be done without the computer on it.

I was sitting here thinking, your engine should still be under the factory warranty also. Make sure that the dealer checks the status on it.

Customer: replied 7 months ago.
Thanks, ***** ***** it is. When I called them last week they told me it is covered until 2019 under the "Gold" plan.

Ugh, Gold is ok, it has its imitations though. Most everything electronic is not covered on it. BUjt if the standard warranty recently expired, maybe the dealer can make a call to Mercury to get at least the parts covered and you only need to cover labor. This can still save hundreds on a repair for even just a fuel injector.

Customer: replied 7 months ago.
Good to know, thanks for the info. I am making a list of all the items we have already tested. Hopefully it will help them isolate the problem a little quicker.

It should, we went through allot of items.

Just as a quick last test, turn off the kill switch, then see if the pumps turn on when the key is turned to run.

Customer: replied 7 months ago.
With the kill switch on, when I turn the key on I get no clicking, beeps, nor do the fuel pumps turn on. I also checked the battery under load and while cranking it drops from approximately 12.4v to around 10.8 v.
Customer: replied 7 months ago.
I meant with the kill switch off.

That is enough battery volts to run the ECU while cranking. I hate to send one in after everything that has been done, so the kill switch was just a thought.

Customer: replied 7 months ago.
I appreciate it, If you think of anything else just let me know. Thanks again for your help. I will let you know what they find.

I would really be interested to know what they find out for sure.

Charles, Marine Mechanic
Category: Boat
Satisfied Customers: 5128
Experience: US Navy (Ret) Certified Mercury Marine Tech with over a decade of repair experience.
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