Surging Ficht

[Nauti Buoy]

I have a 2001 Evinrude Ficht 115 HP, Model E115FPXSIG, S/N G 04955823. Last fall it ran well-no problems at all. I winterized the motor which included: decarbonizing using (Tuner), fuel conditioner for winter storage (2+4), fogging oil (throttle bodies and cylinder), and replaced the fuel/water filter and LU oil. Typical maintenance.

This spring I added system cleaner (5 bottles/62 gal fuel tank); ran the motor in a stock tank (2'Wx2'Hx4'L - 103 gal.) to burn off the fogging oil up to 1500 RPM in neutral; indexed new plugs, and ran again at idle & up to 1500 RPM. Had to watch & correct tendency for RPMs to run up on its own. Stored the boat in the garage, and over the next few days, I noticed more black oil on the floor, just as it had done over winter after winterizing. Thought this was because I hadn't burned off all the fogging oil since some of it may have spilled over into the casing while tilting the motor to set up the stock tank. Thought this was normal.

Launched the boat for first time yesterday. Started on third try (bulb was hard). Smokey – much more so than usual. Felt I was still burning off fogging oil. Took off at idle with no problems, other than still smokey. As I increased RPMs the motor started surging, worse at 2000-2200 RPMs. No surging at higher or lower RPMs than at the 2000-2200 range. Improved over a 3 hr use, but stil have a surging symptom at 200-2200 RPMs. OK at higher or lower RPMs.

What could be the cause?

[Bigcat]

I have the same year,same motor.I would not call mine a surge just a little flutter, with no loss of power, or preformance.
I have also had the softwere up grade all done by a factory tech. what was explaned to me is at that rpm range the computer is in between shifting to a higher mode.
Is it possible you got a wire crossed,or cracked a plug on the install?
I have 465 hrs on my 115 and it runs like a bear.

[Nauti Buoy]

Thanks Bigcat,
I may have around the same amount of time on mine. This is the first time the motor has ever run rough and it was definitely surging - could see the tach changing. Later today, I'll be checking the plugs to see how they fired. I don't believe I crossed any wires as I think there individual lengths would prohibit that.

What is with the software upgrade? What's changed? Or, is this only a diagnostic sofware upgrade for the EMM?

[Bigcat]

Nauti,
The upgrade I had was something Evinrude came up with to tweek the engine,I have the new software but do not notice any diffrence.
The flutter or stumble that I experience is more of a sound,and dose not effect the tach.
Also your exhust sensor tube could be gummed up, you have to take the case apart to get at it,not a big deal.

[Nauti Buoy]

I'd completely forgotten about the exhaust sensor. Had planned on taking a look at it, even replacing it as part of this spring's boat prep. Gotta write these things down! Thanks.