DF350A missing and surging

[Jesse749]

I have a 2018 DF350A on an Avalon pontoon boat. It has approx. 60hours on the engine. Last summer it started missing a little bit so instead of taking it to the dealer I asked a local mechanic if he knew anything about it. He suggested changing the sparks plugs. I did and the problem was solved for the rest of the summer.

I put the boat in the water for the first time this season last weekend. Under throttle it is missing again as well as an alarm going off and then dies. It starts right back up and run fine at idle. Once under throttle the missing and alarms going off happens again.

I spoke with a gentleman on Youtube this week who suggested checking the white wire. I have not been back to the boat yet but will check that first thing. It just seems odd that if it is a loose connection that it starts right back up.

Any easy suggestions to try before I join the 2 month wait at the dealer?

[Moonlighter]

The alarms usually are accompanied by fault codes on the gauges. The fault codes will help diagnose the issue. Any info on that?

Have you checked the fuel filter for water?

Also, modern engines like these are VERY SENSITIVE to poor voltage. So you want to be sure that your batteries are in top condition and fully charged, and all battery connections should be cleaned and tightened.

[Jesse749]

I have not checked the gauges yet. I kind of freaked out when it happened and then never actually looked down at them.

Water in the fuel is the first thing I will check when I get there tomorrow. I went ahead and purchased a new fuel filter so I could just replace it.

Thank you so much for the help!

[Moonlighter]

Ok, you now know that it is very important to look at the gauges and see if any fault codes pop up when the problem happens. If you find codes you can talk to your dealer about what you saw and they may be able to offer suggestions to help you get back on the water, assuming its not a complicated issue.

If its water in fuel, apart from the main water separating filter on the boat’s fuel line, if water has got past that and caused the alarm, then Im sure there is a filter on the engine that will need to be drained as well. Not sure its location etc on the 350 but it will definitely need to be drained if water has got in there, it has the water sensor in the housing.

[Jesse749]

Once again, Thank you very much. I appreciate your help.

[embrym]

Any updates on all these DF350A issues??