06 Suzuki 4 Stroke 115 sputtering

[dctaz37]

I took my boat out for the first time since last November and it started okay but was idling very fast and after a bit an audible alarm was beeping. I shut it off and operated the throttle a few times and it then started okay. I got underway and I would give it throttle and it would go them sputter then go, I trolled for 4 hours no problem but when I went to return, it got up on plain, the sputtered then went again. The plugs are 4 years old and new fuel filter last year. When I winterize it, I disconnect the gas line, run the engine until all the gas is used, drain the gas tank and then put stabilizer + methyl hydrate for whatever little fuel is left. I filled the tank 8 weeks ago but the boat launches closed and never got out. When I took the cover off yesterday, the gas tank was overflowing as I guess it expanded because it was a lot colder when I filled up. I syphoned some gas out.
I was going to starttroubshooting by checking the plugs. Not sure what would be next. Can you run fuel injector cleaner safely through this engine? Any advice would be appreciated.

[catacom225]

Sound s like your in safe mode which means your engine will not rev over 3000 RPM, Turn the ignition on and listen to the error code, It will be a series of beeps example, 3-2 three beeps pause and two beeps
when you work out the code post it

[dctaz37]

The error code was there when I first started it but after I shut it off, moved the throttle back and forth a few times, it started up with no errors. I think the throttle was sticking at first because the rpm's were high.

[Moonlighter]

It would help if you could be more detailed about the revs involved and describe the circumstances when its missing more completely. Bear in mind, none of us can see or hear what is happening with your engine so The more info you give, the more likely it is that someone will recognise what is happening and why, and be able to offer suggestions.

Now, one possibility is that the neutral throttle switch has failed. It does happen. What that means is that the engine still thinks it is in neutral (because it doesn't see the signal from the switch that tells it that the engine is now in gear) and therefore the rev limiter cuts in at about 3000rpm, and also spark advance is restricted as well, meaning acceleration to 3000 rpm is also doughy. If you try to rev the engine in neutral, the NTS stops it being over revved. So ask yourself, does it sound the same as that when you are trying to rev it when its in gear? Its like a race car that is in pit lane with the pit lane limiter. It didnt really sound like that from your description, sounded more like a bad spark plug or plug lead from what you said.

But the very first thing would be to replace those 4 year old spark plugs!! When you take them out, carefully check each plug to see what they look like and if one looks different to the others, thats the problem plug/lead/cylinder.

And you Should NEVER pull the fuel line off and run the engine out of fuel causing it to starve and stall when winterising it, or any other time. This is going to damage the LP fuel pump and should not be done with any efi 4 stroke engine. That could be another cause of your problems - poor fuel pressure.

[dctaz37]

Thanks Moonlighter. In hindsight, I should have taken a video. I hope this helps, leaving the dock I gave the boat a little throttle, I don't think anywhere near 3000 rpm. it would run fine for a few seconds then sputter/bog down sounding like it was going to stall, then run properly for a second or two and surge ahead. I seem to remember it clearing up but It was very foggy and I was following another boat maybe going 4-5 miles per hour not on plane. After 10 min. I got to where I wanted to fish and trolled at 2 mph for about 5 hours, ran fine. On the way back when I gave it throttle it got up on plane for a few seconds, probably revving past 3,000 rpm, sputter/bog down. It continued to go up and down for the 5 min. it took for me to get close to the dock. When I got close, it was windy so I had to fight the wind so I needed more throttle. It continued to sputter/bog down till I got to the dock, probably under 3000 rpm. I'll get the plugs. Is it safe to go over 3000 rpm with water wings or do I need to get it to the water for testing? What about running fuel injector cleaner through it? I guess I could have got some bad gas too. So many things it could be.
In regards to winterizing, do you have a link to a reference for best practises?

[Moonlighter]

#1 Change those old plugs.

Yes its fine to add fuel injector cleaner same stuff as is used for car engines is OK, add to the fuel tank at the recommended concentrations. But if you have clogged up the VST with rubbish no amount of cleaner is going to fix that.

As mentioned earlier the NTS will NOT allow the engine to be revved past about 3000 rpm in neutral, this is to prevent engine damage. I think that once the plugs are inspected and changed, then you need some load on the engine to test it so best to put the boat back into the water, warm it up then take for a run.

Your owners manual will have instructions on winterising. Other members will hopefully chime in on what they do - here in Australia we dont have icy winters anywhere near where people go boating Regularly, so nobody winterises outboard engines here! LOL!

But that doesnt take away from the requirement to NEVER run these engines out of fuel. We used to do that on old 2 strokes to stop the premix fuel gumming up the carbies, but times have changed since then with efi 4 strokes. Its a bad thing to run the electronic fuel pumps on these engines dry.

Try running the engine on a separate fresh tank of fuel to eliminate stale fuel as the culprit..

I assume you have a water separating fuel filter in the line between tank and engine? If so change the element. Tip the contents of the old element out into a glass jar and see what you find.

[artdf175]

Moonlighter is correct on don't run it dry for the various reasons
best thing you can do is to use a good fuel stabilizer and read directions as I am remembering you add a stronger concentration in the winter.
Just add to your fuel tank then fill the tank to make sure it mixes well. Then run your engine for 15 minutes or soThat way the mixture gets into all the fuel system ..
And find a gas station that has non alcohol fuel. very important for winter, especially.
Art

[dctaz37]

image_1866.jpgIMG-20200517-00069.jpg Okay I won't be running the fuel out anymore. I've done this for the last 4 years on this motor and I was doing the same on my 2 stroke outboard for 20 years. I still may drain the tank though. When you say no alcohol, is that ethanol?
From the details above it sounds like 4 years is a long time for plugs, when should they be replaced? I took the plugs out yesterday, I've attached photos. For now I cleaned them up. I did find a bit of discharge in the holes and when I took the plugs out they didn't seem very tight so may not have been tight enough. I then disconnected the main fuel tank and hooked the motor up to a small tank with 1 liter of gas with some methyl hydrate and fuel injector cleaner. It seemed to run fine, I went over 3000 RPM with no sputtering then ran it for 30 minutes at 2000 rpm. At about half way through the rpm went up, maybe something made it's was through.
No I don't have a water separating fuel filter in the line between tank and engine, just the one that came with it on the motor. Will that now catch water? Can you recommend an inline one?
I guess the next step is to get it back on the water to test out. I also added some extra methyl hydrate to the fuel.
The live well pump also stopped working so another project. It looks like it is a Johnson cartridge pump so minus the awkward area, it shouldn't be too hard to change.




IMG-20200517-00069.jpg

[Moonlighter]

We replace plugs every 100 hours. When we do the annual service and change the oil.

no alcohol = dont use ethanol fuel. Ethanol attracts water, and when the concentration of water in the duel exceeds the capacity of the ethanol to absorb it, the fuel separates and is then completely un useable.

It really is essential to run a water separating fuel filter in the fuel line between tank and engine. Efi engines hate dirty fuel or water and getting it into the fuel system will result in expensive and time consuming repairs.

RACOR make a well known fuel filter that is highly regarded and there are several similar ones on the market. This is what the RACOR ones look like, the clear bowl at the bottom has a drain plug that allows you to see water and drain it off. You local marine equipment supply will have them or similar.

https://www.whitworths.com.au/racor-...te-fuel-filter

[dctaz37]

Thanks I will look into the filter. Most of the fuels have ethanol here in Canada except for the premium I believe. What plugs do you use? Thoughts on Iridium? What about the process I did in my description and the condition of the existing plugs? One if my friends recommended using sea foam, thoughts?

[Moonlighter]

We just use normal NGK plugs. Thos ones of yours look well past their use-by date.

A fuel stabiliser such as Stabil is used by many people. I do believe there are outboard fuel treatments recommended for ethanol fuels, so consider using one of them.

I dont know anything about methyl hydrate. Would you put that in your car”s engine? If not, it doesn’t belong in your Suzuki either.

Saefoam? Isnt that a decarboniser? The Suzuki is a modern efi computer controlled 4 stroke, not a carby 2 stroke. Again, would you run that thru your car’s engine?? So stop thinking about this Suzuki as you would an old 2 stroke, there is no resemblance at all above the leg.

Suggest you deal with the plugs first and see the results.

[Murray]

For your ethanol question. For the most part premium fuel is ethanol free but not always.

https://www.pure-gas.org/index.jsp?stateprov

Methyl hydrate can be used in your boat, it’s the same as “Gas Line Antifreeze” not sure exactly how it works other than it “emulsifies” with the water and allows your engine to burn the water somehow. The correct amount to add will be on the label. Make sure on the instructions that it states “ Safe for rubber O rings” SeaFoam will also do the same thing, both treatments are for small amounts of moisture. I’ll add Gas line antifreeze to the vehicle before a cold snap is about to hit.

[Moonlighter]

For your ethanol question. For the most part premium fuel is ethanol free but not always.

https://www.pure-gas.org/index.jsp?stateprov

Methyl hydrate can be used in your boat, it’s the same as “Gas Line Antifreeze” not sure exactly how it works other than it “emulsifies” with the water and allows your engine to burn the water somehow. The correct amount to add will be on the label. Make sure on the instructions that it states “ Safe for rubber O rings” SeaFoam will also do the same thing, both treatments are for small amounts of moisture. I’ll add Gas line antifreeze to the vehicle before a cold snap is about to hit.

Thanks Murray. Great info.

Googled and methyl hydrate is methanol. Another form of alcohol. So probably works the same as ethanol by taking a certain amount of water into solution which can then be burnt. But like ethanol, once the water concentration reaches a critical point it will likely phase separate.

I dont know about the wisdom of adding it to ethanol blend fuels - whether they all play nicely together or might cause issues with engine of fuel system components if the alcohol content is too high? I know that here in Aus, Suzuki says that E10 is OK to use but nothing higher than 10% ethanol.

[dctaz37]

Took the boat out on the water today and it wasn't as bad as before but there was still hesitation and bogging down. I'm going to replace the plugs next. My book says ngk bkr6e Resister type. Is that a special plug and is resistor required? Also, I mentioned that my live well pump failed so I swapped the cartridge style pump with the live well pump I don't use. Now the pump leaks around the o-ring. There is some sort of sticky substance around the o-ring and I suspect there isn't enough. Any idea what the substance is?