Engine surging randomly....

[OHLNautique]

Yesterday we were cruising up the river and the engine started acting like I was running the throttle back and forth. I slowed to idle and the boat ran fine. I sped back up and it ran fine for a while then started doing it again. It continued to randomly surge all the way back home. The boat idles just fine and I can run the throttle up in neutral and it runs fine. It only seems to do it under a load. I suspect a fuel issue but I guess it could be electrical too. There seemed to be a rich exhaust smell related to the surging. The boat is an 08 210 signature with the 5.7. It's only got 25 hours on it. Any suggestions? It's going to the dealer tomorrow but it would be good to give them some direction.

[SGY]

RE: Engine surging randomly....

Do you have perfect pass or Zero Off?

[OHLNautique]

RE: Engine surging randomly....

I have zero off. It was turned of when the engine started acting crazy. However, I am suspicious if maybe the Zero-off is screwed up. Anybody had this sort of trouble with it?

[OHLNautique]

RE: Engine surging randomly....

I need to mention that the surging is not consistant. In other words, it does not go from 3500 Rpm to 2500 back to 3500. It jumps all over the place. Yesterday when I drove it to the boat ramp it did it so bad that the boat came off plain and almost quit running.

[Andrew]

RE: Engine surging randomly....

is it possible that there is water in the tank? how long has it been since the last fillup?

[OHLNautique]

RE: Engine surging randomly....

Filled it up the morning it started doing it. I have a portable 25 gallaon tank that I take to the gas station, fill up, then wheel it out on the dock. Marina gas is too expensive. I guess its possible that the portable tank could have water in it. However, I have used it several times and the problem just started. How do you check for water in the boat's fuel system?

[AirTool]

RE: Engine surging randomly....

Drain the FCC bowl into a funnel / hose through the hull and into a mason jar. Let settle and look for gas /water interface.

AirTool

[OHLNautique]

RE: Engine surging randomly....

Got it back today. Dealer says fuel filter was full of crap. Possibly debris in the tank from the factory or in the tank I use to fill the boat at the dock. I suspect the later. Anybody know how to clean a 25 gallon portable tank?

[TravisFling]

RE: Engine surging randomly....

Burn it out!!! Just kidding... If it's a close cell tank with (I assume) an air port that you can open and close at the top (?) then I would.... hmm... All the ideas I keep coming up with leave me unsatisfied... I've always heard it's better to have a little dirt in there than water, and whatever you put in there will leave residue that will make it's way into the engine. I would see if I could get an in-line filter for the hose from the tank to the boat, and then clean that regularly. I wouldn't really want to put anything into my gas supply that would end up in my boat's fuel, you know?

[OHLNautique]

RE: Engine surging randomly....

That's a good idea about the in line filter. I'll do some searching to see if I can rig something up. I can't think of any way to "wash" a big gas tank other than to flush it with more gas. That might get expensive unless the gas could be salvaged/recycled. Thanks.

[JUST-IN-TIME]

RE: Engine surging randomly....

acetone my friend