New Guy at wits end

[tony kiehle]

I have 1.5 year old boat with this random reoccurring problem that the dealer cant seem to figure out. The motor is a 2015 DF 250 on a 24 FT Thunderjet Pilot. Below is my best description of the problem:
• As your running the motor will drop RPM it doesn’t seem to sputter it just seems to drop RPM, you can push the throttle lever all the way to the stops and nothing happens it just sits there and will not go over 2500 RPM.
• You have put the motor in neutral turn it off and restart and then it seems to be good to go.
• There is no set RPM that I have noticed that it occurs at.
• It has happened I am guessing 8-10 times now.
• I might go 2-3 trips and it won’t happen there seems to be no pattern here.
• A couple times I have had to restart the motor twice in order to get back to normal.
• I have replaced the fuel water separator filter twice just in case.

As of now the dealer has replaced the fuel filters and pumps, used a test computer still did it, pressure tested the fuel system twice, drained the tank and replaced the fuel.

Any thoughts would be appreciated

[Harper]

I'm thinking it's the fail-safe system kicking in. This is different than the self-diagnostic system, in that you get no alarms, and no flashing CEL, only a reaction from the ECM that limits the output of the motor. What happens is that the ECM assumes a fixed value for a sensor that it assumes has failed. Since this condition would result in potential damage if it continues (e.g., a very rich fuel mix or extremely lean condition), the ECM will limit RPMs until it is once again receiving the correct information from the faulty sensor. It's basically a limp-home mode. When you say the dealer "used a test computer" I assume you mean he put another ECM on the motor. This ECM would also get the same intermittent signal failure from a sensor, and react the same as the original ECM.

Since this is occuring intermittently and can usually be remedied with a shutdown and restart, I would first suspect a faulty connector, then a failed harness (bad splice or broken wire).

[tony kiehle]

Thanks Mike, that seems logical especially since they are getting no error codes on the computer and yes that was what I meant by test computer.

I will pass it on to the dealer.

[jHydroman]

If you are in WA I would take it to Puget Marine in Olympia, small Suzuki dealer with great service.

[Harper]

Good luck Tony. Let us know how things turn out.

[redlowrey]

I have 1.5 year old boat with this random reoccurring problem that the dealer cant seem to figure out. The motor is a 2015 DF 250 on a 24 FT Thunderjet Pilot. Below is my best description of the problem:
• As your running the motor will drop RPM it doesn’t seem to sputter it just seems to drop RPM, you can push the throttle lever all the way to the stops and nothing happens it just sits there and will not go over 2500 RPM.
• You have put the motor in neutral turn it off and restart and then it seems to be good to go.
• There is no set RPM that I have noticed that it occurs at.
• It has happened I am guessing 8-10 times now.
• I might go 2-3 trips and it won’t happen there seems to be no pattern here.
• A couple times I have had to restart the motor twice in order to get back to normal.
• I have replaced the fuel water separator filter twice just in case.

As of now the dealer has replaced the fuel filters and pumps, used a test computer still did it, pressure tested the fuel system twice, drained the tank and replaced the fuel.

Any thoughts would be appreciated

'''Do you want to explain in a bit more detail, you had to start it a couple of times before it come good, and is it a df250A or a df250, My guess it is a df250A with electronic throttle control.