2004 Johnson DF 140 Sudden Loss of Power and Tapping

[Captwill_80]

Ok, so today we ran about 90 minutes to the jetty for the first time. Even went a mile or so out and the boat ran flawlessly. On the way back in I was cruising along at about 4800 RPMs and decided to open it up. We got up to about 5600 rpm and were moving along nicely. After about 10 minutes I started loosing power. At full throttle I went from 5400 to 4000 and started to hear a clicking sound. No alarms but I shut it down. I waited a bit and it started right back up but would not get on plane. The clicking sound can now be heard at idle. It's idles just fine and is very smooth. I'm currently staring at a pair of Merc 150's on the boat us tow boat so I haven't done anything but check the oil (full and normal color) and the spark plugs (all tight).

Any thoughts? I have a video of the noise but I don't think I can upload it from my phone.

[Captwill_80]

Videos at idle and then fast idle

https://youtu.be/nnQUdAYylWc

https://youtu.be/NlQyRGr04HQ

[artdf175]

This has some of the signs of fuel starvation
What is the condition of the fuel bulb?
Checked or replaced the fuel filters?
Condition of fuel?
Art

[Captwill_80]

Drained the tank for storage and changed the filters. The tapping sound is odd unless it ran lean and dentonated causing damage. The tapping was not there before.

[artdf175]

Couple more to check
Fuel primer bulb
Next time you run it comparable time
I still suspect a fuel tank venting

[catacom225]

Hi Captwill,Have you pulled the plugs out and inspected them, they might give you a clue on that tapping noise

[Captwill_80]

So I'm told it's a wrist pin and need to rebuild. That's without pulling things apart. Does that sound right based on the fast idle video? The sound is coming from around the top two cylinders and it at first sounded like the head area but it is more towards the cylinder walls.

[Moonlighter]

That sort of knocking noise is never good. I wouldnt be surprised to find the kind of damage you have been told, or worse. Was on board a friends boat with a Yamaha a few years ago, and suddenly found we had a loss of power and similar noise - it had lunched a couple of pistons....... alloy plastered all over the plugs when we pulled them.

The question is, what condition is the rest of the motor's intenals in, and is this all that has happened in there, and is there an obvious cause, or just wear and tear? You dont say how many hours it has on it...... and a rebuild would run to quite a few $$$$ unless you can do it yourself, and even then you are left with a quite old motor.

You probably wont really know until they pull it down, but you would certainly want to check the engine holder at least, as they are subject to corrosion on those early 140's.

It is after all a 13 year old motor, it was the first generation of the Suzuki 4 strokes so it is getting long in the tooth ....... and the current 140A is effectively Gen 3 technology and almost a completely new beast, so depending on what you find, may want to consider parting it out and updating to a new one.

Good luck, let us know how it progresses.