Suzuki 115 4 Stroke

[hazlux]

I purchases a used boat last June with a Suzuki DF115 ( 2003) with less then 500 hrs and been having some major issues. I have had two mechanics look at it and still not fixed.

I ran the boat with no issues for about 2 months when it began to surge and or bog down.It acted like it was getting enough fuel, water in the fuel or something restricting the fuel injectors. The first mechanic clean the fuel injectors and replaced the #4 spark plug that was burned. It ran great for another 2-2-1/2 months when it started doing the same thing.

I took it to a certified Suzuki mechanic, he ran a computer diognostic that came up clean. He went to pull the spark plugs and the #4 plug had seized in the thread, it took him two days to work it out. He replaced the # 4 plug again and we ran it for another 2-3 months and it ran great. Then once again it started to act up again.

Once again I took it to the Suzuki mechanic, the plug was stuck again but not as bad, he replaced the #4 plug again and it is running great but starting to get a little hesitation when taking off ( same symptom as before) and I am going on my 2nd month.

Last time I brought it in and put it up on the rack I went to check the #4 plug and it was extremely hot and I could not get the plug out, I could not even move it a bit.

My mechanic wants to pull the head and see if there is a bad gasket or crack allowing moisture to get inside the motor. I am torn with dumping a couple of thousand dollars into it with the motor being 12 years old and he is not sure what it may be.

Has anyone ever had similar issues?

Any suggestions?


Thanks

[Seaduck]

Really hope you figure it out. I had a small hesitation on take off when I purchased the boat. Its a Carolina skiff with 2007 115 Suzuki. I replaced all fuel lines outside and under the cowling. New fuel/water separator, new low and high pressure filter. Still hesitation on takeoffs. After someone mentioned it I pulled the overflow hose that runs from the top of the vst tank to the head. fired the motor up and in seconds fuel started pouring out. needle and float inside tank were shot causing fuel to excessively fill the tank and dump back into crankcase. Noticed when I checked oil it would rise after a day on the lake. took the vst tank off which sucks but did it and replaced everything inside. pulled overflow hose off and every blue moon might get a drip but otherwise dry. boat fires out of the hole now. I know its not a hot plug issue but mine did have that hesitation you are talking about. other guys will get on here soon and can help more im sure. good luck bud.

[Solarman]

df115, #4, plug seizing

Or, could be water not cooling that that cylinder, if getting that hot as you said. Maybe some of the water passages for that cylinder are partially blocked?
Just thoughts. Good luck.

[catacom225]

plug seizing

Good point Solarman.
When i got my 140, it looked it had never been flushed.
The water jackets around the pots had a ceramic like build up ,crystallized salt i would imagine .
With his engine tilted up for long periods it could allow crap to block water to cylinder 4

[Solarman]

df115, #4 plug seizing

Hazlux, think before tearing apart for the big bucks, I'd find a large container/tub that I could put the motor in and let it idle/run with 5 - 6 gallons of vinegar and enough water in the container, or another good flush solution, for 3 - 4 good hours (if temps allow), can do in multiple stages. But check temp on bottom cylinder as you flush if able. Can't buy a tub, or container? Can make a box of cheap wood your motor can fit down in, line it with several large trash bags, add water and vinegar. Pull bags up to catch pee stream, and exhaust. If #4 starts cooling down similarly, compared to other cylinders equally, then I would change plug again, and see if it is still doing same thing?

It is possible that #4 may be running too lean, and causing such high temps to seize the lower plug, but for the cost factor, think I'd try flushing first? Your call.

Good luck, keep us all posted how it's going.

[hazlux]

Thanks

Or, could be water not cooling that that cylinder, if getting that hot as you said. Maybe some of the water passages for that cylinder are partially blocked?
Just thoughts. Good luck.

Thanks for the comments all.

I am going to take a look at the coolant system and see if we can find something.

I will post back once I take a look

Thanks again !

[redlowrey]

You should be able to tell just by looking at the plug whether that cylinder is running hot or it is getting water in

[WEDOCQ]

Get a $15 infrared thermometer from Harbor Freight, and use it to check temps around your head. If you show a temp spike around the #4 cylinder, I would guess there is a water passage that's clogged. Salt Away in a garbage can works well also.
-Shawn

[hazlux]

Thanks

Thanks for all the ideas.

I took it to yet another mechanic and boy what a mistake !!!

I found the problem the #4 cooling chamber was about 90% clugged with corrosion> My new mechanic had my boat for 6 weeks and charged mt $2800 to drill it out the chamber, pressure checked it for cracks, check the specs,acid wash, new piston rings, thermostat some seals and new bearings. I ran it for about 2-3 hours and it acted up again, I took it back and the found a small hole inside the chamber they claim the pressure check did not find.

They weld it shut and I am to get it back this week.

Anyone have knowledge on how a weld holds up?

The engine is about 12 years old but only has about 500 hours on it.

Thanks again for all the input! I hope this time it works

[straycatboat]

I have a pair of 2002 140's that the water jacket corroded into the exhaust valve chamber and the heads cost $3000 to replace, now they are just parts engines. Both failed the same way.
The previous owner probably never flushed the engine or replaced the internal zincs.