Engine Cut Out At High RPM's

[Snowman]

Engine: 2002 OX66 200hp. During my last run of the Florida season before returning north my motor began cutting out while running at 25 mph. Without warning or any other symptom the motor would stop. I could restart without problem and run at idle. The boat would throttle back up to 25 mph and run a couple minutes and the cut out suddenly. This happened perhaps 5 times before I was close enough to my slip where I could travel the rest of the way at slow speed. It acted exactly like it would if I had suddenly run out of gas. No sputtering or gradual slowing just a sudden stop but easy restart. I checked the fuel/water separator and found no water but it did contain black fleck like particles. Could this be a symptom that my fuel line is deteriorating and clogging my filters? I use fuel that contains methanol but use Stabil Methanol treatment. Since I was leaving in two days I had to leave the problem unresolved to be addressed when I return. Can anyone offer any ideas as to what I need to do to find the problem. I typically run offshore some distance and I won't feel comfortable doing so until this issue is diagnosed and resolved. Thanks!

 

[lorikay2]

My first guess would be that it’s the high pressure fuel pump. Next, it could be that your fuel pick up is getting clogged by debris in the fuel tank. I wouldn’t really think that the fuel filters are getting clogged up by bad fuel lines. But might be worth the cash for “peace of mind” just to replace them both. good luck. hope you find it!

 

[DaleH]

Check your battery terminals. Put a large SS lock washer down on the terminal posts BEFORE your leads. Then your leads and a nylok locking nut, and NOT wing nuts. SS internal or extrenal tooth lock washers between leads are great too.

Sounds electrical to me ...

 

[John_Madison CT]

You should start with:

1. Replace VST Filter
2. Replace low pressure fuel pumps.
3. Clean O2 sensor.


After those things are done, and assuming you still have problems, you can start looking at more complicated things.

 

[fogwarning]

I don't know - but why replace things that may or may not be wrong, especially if they cost real money? Considering you take her offshore, you NEED to know it is fixed right. Since you don't know what the problem is, I would suggest taking it to the shop and have them figure it out. Then you can either fix it yourself or have them do it. Just my .02.

Good luck either way!

 

[John_Madison CT]

All 3 of the items I mentioned in my post are part of regular maintenance. The VST and O2 cleanings are annual. The Low-pressure pumps are suppsoed to be done at 3 years.

If you haven't done them, you should. There's a good chance this will fix your problem.

 

[Snowman]

Had my annual done last fall. Not sure if the O2 sensor was looked at. I'll check with the tech who did the work. One suggestion was that I take the boat out with a couple 5 gallon containers of gas. If the problem occurred disconnect the fuel line from the bulb, attach a length of fuel line and run the motor from the gas cans. If the problem did not reoccur the problem is from the main fuel tank to the bulb. If it did reoccur the problem is in the motor. That would at least eliminate one or the other.

 

[TomS]

I think you were on the right path with your original diagnosis.. other than the common maintenance items mentioned above, your problems could also be caused by a deteriorating fuel line. A boat next to mine had a similar problem with the same motor of a similar vintage, the fuel line was deteriorating from the inside out, so the problem was not immediately visible. I would take your own suggestion and try running on a separate fuel line to a portable tank and see what happens.

I replaced all my fuel lines (boat and motor) a couple years ago after seeing the problems he had, glad I did.

-- Tom

 

[fogwarning]

Well, not sure about the spare fuel tank idea. Sure, the fuel line may be the root cause of the problem, but if those little pieces have gotten past the filter and has clogged some of the passage ways in the engine, it won't show that... meaning the problem still exists... It seems logical though that it could be contibuting to your problem as you mentioned finding black specks in the fuel filter. Hopefully, the filter is doing its' job and keeping that from getting to the engine.

 

[DaleH]

Sure, the fuel line may be the root cause of the problem, but if those little pieces have gotten past the filter and has clogged some of the passage ways in the engine, it won't show that...

I believe what Tom means is that the ID of the fuel line collapses on itself and thus starves off fuel delivery ... akin to a clogged artery ...

 

[fogwarning]

Interesting theory and one I had not considered. In that case, I agree a test tank and fuel line would be a good test.

 

[Snowman]

My boat is a 21se. How difficult is it to run new ethanol "safe" fuel line from the tank to the motor. From the water separator to the motor is not a problem. I have an access panel in front of the console. I have never opened it. Would this give me access to the fuel tank where the fuel line originates? If yes, then I would assume I could secure the new fuel line to the old and pull it back toward the stern as I removed the old line. Does this sound reasonable?

 

[TomS]

On my 1999 21DV, the fuel line ran right from the tank fitting, over the tank and straight back to the port side transom where it was secured with wire ties. It did not run through a rigging hose or anything, and was very easy to remove once I was able to squeeze my arm in and snip the wire ties. It should be pretty easy.. try following it back from the engine as far as you can with your hand.. also, it may sound stupid but you can use a digital camera (or video camera) with a flash to take a bunch of pics of areas you couldn't ordinarily reach or see.. I found that to be a great help.

Good luck, its an easy job, well worth the time/effort.

-- Tom