DI20 bogging down

[Haese56]

This motor is 4 years old with very low hours on a pontoon boat. I was out with my grandsons and as other have reported the motor suddenly bogged down. I cant remember if it shut down but we limped home. Suspecting a fuel problem I disconnected the tank, ran the engine dry (it seemed to idle OK), cleaned the tank and line fresh fuel with sea foam, let it soak overnight, drained the semi transparent blue fuel filter(?..... seems like just a plastic resevoir to me) a couple times... also drained the drain screw a couple times. The engine fires up ok, WAS idling ok (now it’s dying out unless I give it a touch of throttle) but when I try to run up the RPMs it goes so far and then starts loping or bogging. I’m a bit off the beaten path in Alaska so getting it to my dealer will be a challenge but I will if I have to. Is there someplace else water or dirt could be hanging out that I’m missing? I WAS getting a 3 and 2 flash code on my engine light briefly when I refueled but I think this was because of a heavy does of sea foam in my fuel line/bulb.

[Haese56]

Actually I guess it’s a DF 20 HP pulled both plugs (not reall easy hanging upside down off the back. They both look great. Pulled the far side off the fuel filter, seems like plenty of fuel getting through. Started getting the 3-2 flash signal again but I’m thinking this may be from a heavy shot of sea foam coming out if the bottom of that filter again? Looks like a trip to the dealer unless anyone has any other ideas. I’m trying to find my warranty paperwork, probably 4 years since mine is 4 years one month old LOL

[Murray]

A 3-2 code is a MAP sensor 2. The service manual has a test procedure to test the sensor. I wouldn’t think SeaFoam would cause a code.

[Haese56]

Been messing around with this motor for a couple days. It’s thrown the 3-2 code twice, once right after I gave it a does of almost pure sea foam through the bulb.... and again today when i disconnected let some fuel flow then reconnected the fuel filter. I have pretty good confidence in my local shop. Just bummed that I’m 40 days out of warranty. Just guessing I doubt this motor has 50 hours on it... certainly no more than 100

[Murray]

Was just reading in my service manual (2009 DF90A) that the TPS (Throttle Position Sensor) is tied to the same circuit as the MAP sensor. Not sure if your newer engine has the same sensors that I have but I would assume they would have similar setups. The data from the MAP sensor tells the ECM the fuel injection duration and timing, the TPS determines the voltage signal going to the ECM which inturn determines the control mode of the various other control systems (Idle air control, fuel injection control systems).

Did you look for loose/corroded wires around the sensors? I can’t see SeaFoam affecting a MAP sensor, fluid shouldn’t be able to get into a pressure sensor. Could be wrong though.

[2014DF25ARS]

You say your motor is 4 years old, which means it's a DF20A rather than a DF20, correct? Is it fuel injected? I have a 3-4 year old DF25A fuel-injected motor. A month ago it "bogged down" after about 20 minutes of cruising on a river at moderate speed. It felt to me as though starved for fuel. We limped home effectively at idle speed for about 30 minutes. After a few tries at things like you've done, I took it to a dealer for warranty service. The dealer said it had probably gone into "limp mode", which he said will limit the RPM to 1500 (essentially idle). Honestly, it hadn't occurred to me that this might be true, because it felt the same as what happens when I forget to connect the fuel line to the tank!

I ended up needing my boat back before the dealer got to it (they took longer than they expected), and I replaced the "in-line fuel filter" which sits between the Vapor Separator and the high-pressure fuel filter, and this seems to have fixed my problem. The dealer suggested the fuel filter may have caused the motor to run lean, which could cause it to ping/knock, and he said this would trigger a knock sensor which would put the engine into limp mode. His theory is believable based on my experience with the motor. One thing is that as I was tinkering with different things on the motor, I would turn it off to clean a filter or replace the primer bulb, etc. And after each tinker I would start the motor again and it would run normally for maybe 5-20 seconds and then bog down. Each time I re-started, it would run normally for another 5-20 seconds and then bog down. So it makes sense to me that when you shut it down, the limp mode is reset. But when I start it again whatever condition caused it to go into limp mode will occur again, and it will go into limp mode again.

I don't have the SDS diagnostic s/w, but I suppose if I did, I could use it to see what condition caused my engine to go into limp mode. Regardless, for the time being I'm convince I fixed it by replacing the $20 in-line fuel filter. It has run normally for 4 outings since replacing the filter.