Suzuki DF140 Safe Mode

Ringo

Crew Member
hey guys,

I did the regular service on my 2005 DF140, oil and filter change, spark plugs, leg oil, greasing the nipples and the throttle shifters inside the motor and also replaced the Racor filter. There’s 360 hrs on the engine and we took it out last time before the service it was purring like a cat.

When replacing the Racor, I filled it up with non-marine regular gas (3-4 months old) and fired up the engine. The motor sounds like it’s running pretty rough. I took it out on the water and filled the tank with fresh marine grade gas but it was still limping, not going over 3200 rpm and even at that level, not going over 8 knts/hr.

One of the forum members here who’s pretty knowledgeable with these engines was kind enough to send me copies of the shop manual which I used to drain the VST and the HP filter. I also drained the Racor filter in a clear jar and there was no sign of water or debris in the fuel.
Added some Seafome to the tank and let it run idle for good 20-30 mins. Still sounded rough and wouldn’t go over 3200 rpm when on the water. There’s also a lot of fuel odour which makes me think that the motor has put itself in the safety mode.
I’m pretty much stuck at this point. Any idea what else could be the culprit? I’m trying to avoid taking it to the shop in the middle of this Covid cr*p but I also don’t want to cause damage to the motor. Any tips would be highly appropriated.
 
That sounds like spark to me...check all coil packs, and pull plugs if you can. Start with ground connections.
 
One way to check coils is to fire motor up and using a pair of insulated pliers pop one cap off at a time and putting back on. Each one you pop off when running you should hear a change in the motor put back on and go through them. If you pop one off and there is no change in the motor running then there's a good chance you have found the faulty coil, spark plug or even injector. Plugs on most motors should be changed out every 300 hrs, I know many that run them forever but that is a good time to change them to ensure a simple spark plug doesn't wreck your day on the water at some point. You can disconnect and reconnect injector plugs the same way to see if it's one of them. If that doesn't work may need to be plugged in to diagnose for possible faulty sensors.
 
Thanks guys. Keep the tips coming please!

I pulled the plugs out yesterday, checked all of them and didn’t see anything unusual. They are brand new anyway but what are the chances of having Factory-defective new plugs??
I haven’t checked the coil side just yet. I also drained the racor and opened the filter, check the Orings and put it back again. I haven’t touched the hoses on the Racor side but now I’m going to check for loose clamps. Air trap is a possibility but I’m with @ab1752 on possible plug/electrical issue. I’ll check the coil packs tomorrow. Should I also change the HP filter?
 
I PM'd you. Do you have a fuel pressure gauge, the inline type by chance? I'm sure you check it all already but look at the fuel lines when it's running and make sure no lines are collapsed...inspect the heck out of those plugs and the coil packs too. I had a weird intermittent issue last year and the post for the coil had actually broken off but the boat kept running until the lead spat off the coil...
 
Pull all the plugs and make which cylinder they came out of...see if they all match something weird is happening clearly you mentioned it is smelling of gas? How does the oil look on the dip stick?
 
it’s something simple but your missing it.

Sounds like spark to me as well. This might seem obvious but you didn’t cross a spark plug wire by any chance did you. Check your wires to make sure you never pulled one apart inside and it’s not getting current through to the plug.
 
I heard the videos and I'm pretty sure its spark. It sounds like a misfire lean condition and it's running ****** through all rpms.

Need to see those plugs make sure fuel is present and hit it with a compression test. Be great if the old plugs are present to swap back in...
 
I'd say its sucking air somewhere, connections to the fuel filter it is a older engine and the rubber ends do crack
 
I had a similar problem after my recent service. The only thing I could find is that I overfilled the oil by about 1cm on the stick. Took it back out after draining the excess & it ran fine. Have a couple of hours on it since & all is well.
I have since changed how I check the oil level, because the angle of the motor can change the level on the stick quite a bit, it seems.
I now put a short level on the fuel rail & get it plumb before checking the oil level. The only way I could figure to get consistent readings.
Not saying this is your problem, but it’s worth a check.
 
Dr. @ab1752 was bang on with his diagnosis. It was a bad plug. There’s no gap on this one, the other three were all pre-gapped at 25. @Captain PartyMarty - It never occurred to me that I needed to check the gaps on brand new plugs as I was told be the dealer that they were all pre-gapped already. Something to remember for future.

Put the old plug back in and it’s working like a Swiss watch again.

upload_2020-5-18_12-38-52.jpeg
 
Dr. @ab1752 was bang on with his diagnosis. It was a bad plug. There’s no gap on this one, the other three were all pre-gapped at 25. @Captain PartyMarty - It never occurred to me that I needed to check the gaps on brand new plugs as I was told be the dealer that they were all pre-gapped already. Something to remember for future.

Put the old plug back in and it’s working like a Swiss watch again.

View attachment 53067

Well there yah go, glad to hear it was simple, usually is.
 
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