2011 Mercury 115 4 Stroke - bogging down at mid/high throttle

[EuropeanAM]

Ok- at least we can expect relatively even performance.

See very few problems on this model- other than plugs and possibly restricted/dirty injectors.

Try unplugging the injectors one at a time (engine running) and listen for a change in engine running quality. Don't panic if it sounds a warning horn (just be sure to inform the next technician to work on it what you did).

ALL cylinders seem to be the same as you unplug them, or does one make little/no difference?

[freetime]

See very few problems on this model- other than plugs and possibly restricted/dirty injectors.

Try unplugging the injectors one at a time (engine running) and listen for a change in engine running quality. Don't panic if it sounds a warning horn (just be sure to inform the next technician to work on it what you did).

I got crazy last night and pulled the fuel rail and injectors. I cleaned each of the injectors by running some seafoam through them while pulsing them. Didn’t seem like anything was clogging but they should be spotless now. Seems me to be working great.

Its headed back back to give her another run tonight with refreshed gas again and some fuel system cleaner.
We will see what happens

[EuropeanAM]

If you note an improvement, I would suggest that you plan to have those injectors PROFESSIONALLY cleaned, serviced and calibrated during your "off-season".

[freetime]

If you note an improvement, I would suggest that you plan to have those injectors PROFESSIONALLY cleaned, serviced and calibrated during your "off-season".

drained 100% of gas out and put in 12 gallons of fresh with stabile and sea foam.

Took her out just now.

This video shows the idle to full throttle with very slow acceleration.

shortly after this is got worse to the point I could not get up on plane at all and I idled her back to the dock. To say I’m frustrated is an understatement.

[freetime]

I’ve been going back through everything I’ve done and have to ask about the first thing. The very first thing I looked at was the air filter. It was the original foam style that Mercury recalled. It was in terrible shape with entire pieces of foam gone. I replaced it with the new strong mesh style....but is it possible a small piece of that foam got sucked in and is clogging air flow?

Everything Ive been looking at since replacing the air filter has been fuel related. Could it be worth looking at air flow issues?

I sure appreciate all the time and advice

Thanks
Dave

[EuropeanAM]

Dave- that's not impossible, but it's really not that likely. I tend to think you are simply down on one or more cylinder (not making power) due to an ignition, fuel or compression problem.

ONE of the basics is MISSING.

[freetime]

Dave- that's not impossible, but it's really not that likely. I tend to think you are simply down on one or more cylinder (not making power) due to an ignition, fuel or compression problem.
ONE of the basics is MISSING.

What would your next step be?

Possible Im not providing enough power from battery? In all the tests it seems better off the bat and gets worse with time, the only thing I can relate to that is battery to push the fuel

[EuropeanAM]

Cylinder Misfire Test with the Computer Diagnostic System, with the engine under load (3000 or higher RPM's).

Record results for EACH cylinder and use them to help narrow down the "field" of potential problems.

[freetime]

Cylinder Misfire Test with the Computer Diagnostic System, with the engine under load (3000 or higher RPM's).

Record results for EACH cylinder and use them to help narrow down the "field" of potential problems.

Last night I went ahead and pulled the FSM and went through internal fuel lines again. Ive tested both pumps and they are operating good. After reading and reading so many things with exact symptoms as mine I went ahead and got a new float for the FSM. I cant seem to find anything online with a way to test it. Seems to be a major issue with these motors that Mercury has recognized that they get stuck in the high position. No one locally had it so the new one will be here tomorrow. Keeping my fingers crossed.

[EuropeanAM]

Tests are pretty simple- open/closed switch, can be tested with an ohm meter, and monitored with the Computer Diagnostic System (or even a vacuum gauge if you're a little bit creative).

If you need one in the future- Rhonda keeps at least one in stock.

Check the Reference Hose while you're in there and make sure it's in good shape.

[freetime]

Well the new float in the FSM solved exactly nothing. Ugh!

[EuropeanAM]

Cylinder Misfire Test with the Computer Diagnostic System, with the engine under load (3000 or higher RPM's).

Record results for EACH cylinder and use them to help narrow down the "field" of potential problems.

This is likely one of the only methods that is going to produce usable results (odds of throwing the right part at it randomly are pretty low).

[freetime]

This is likely one of the only methods that is going to produce usable results (odds of throwing the right part at it randomly are pretty low).

Thanks. Im trying to find a shop in the area who has the CDS and can get it in soon, best Ive found so far is 5 weeks.

[EuropeanAM]

That's probably about the norm this time of years for any "good" shop.

[freetime]

I think we are getting somewhere!

[freetime]

That's probably about the norm this time of years for any "good" shop.

Well, I found a bad coil on Sunday in the #2 cylinder. Was able to get the part on a Sunday, popped it back in and she was sounding great in the drive per my video.

Took it out on the water and she was running incredible, see video


After about 15 of performance like I havent seen in quite sometime, she started acting up again. Back home, everything checking out but not done yet...getting closer.

[freetime]

That's probably about the norm this time of years for any "good" shop.

Well I broke down and took in it about 2 weeks ago.

I’m not one to pump companies for service as I kind of expect it but it’s something you don’t find much with marinas it’s seems. That said, everyone at the dealership was fabulous. From my first phone call they tried over the phone without bringing it in. Once I decided to, they were on it. They set we up with "my tech" named and it was game on who spent 30 minutes with me in the parking lot and dropped it in the water for a test. They communicated with me on what was going on and made me feel like they gave a crap. I’m not saying it didn’t hurt to scratch the check but it was one of the best customer experiences I’ve had in along time.

What did they find......

The first call was a week ago ish. Vent canister and pump seals, high and low pressure within the FSM(fuel system module). They had to order one of the parts.

Second call was Thursday afternoon. Bad Float within the FSM(fuel system module). This was troubling since I replaced that. They think it was a bad part even though it was a Mercury part, getting the part warrantied so I can get the $132 back. They went ahead got a new one it and installed it today.
Put it on the computer and and ran a full scan everything looked great! They dropped it in thw water and confirmed what the computer said, running great.


I picked it up yesterday and with much nervous this I headed to the water for test run.

Result..... i’m now questioning whether I ever saw the full potential of what this thing had! I will say I was running with very little gas, no trolling motor batteries, no gear and only me so it wasn’t the normal weight load in it but I was getting 6 to 10 mph more than what I’ve ever seen this boat get! I was holding her back below 5800 RPMs but she had more in her. Throttle was more responsive than ever before.

Time to load all my gear back in and get to fishing! Thanks for the the good words through this!

Dave

[SilverFox579]

Happy to hear problem's solved!

[alanhore]

That float must be a very common problem. Had the same issue with my 75 4s this early spring. Glad ya got her sorted out.