Motor Problems 2003 Yami OX66 250's

[Aquamist]

I have a pair of 2003 Yamaha OX66 250's, Im having a problem with my port motor cutting out after a long trip. It will be fine all day then all of a sudden it quits, I hit the key and it fires right up , will run for a bit and quit again. My yamaha mechanic is stumped, I put a third battery in it thinkin they were getting to low after being anchored all day with electronics on, I had all the injectors cleaned and replaced fuel filters. Does anybody think it could be my floscan? Any help is greatly appreciated!!! thanks

 

[Tucker]

Could be a bunch of things. What has you Yami tech checked for? Is he a real Yami tech?? Those are tried and proven engines and you have an unusal problem. Have you checked for fuel starvation when it wouldn't start?

 

[bayrat]

As Tucker said..could be a bunch of things...Single fuel tank, right..not separate?

 

[seasick]

Usually but not always when a motor suddenly shuts down, especially under power, and restarts, it is an electrical problem.
Since it happens after a trip, it could be temperature related but once again , if something goes amiss due to heat, it usually won't start right back up until things cool. Try to see if your gauges fluctuate when it happens. That would confirm an electrical issue. I don't think floscan is the culprit but to eliminate it you could remove the sender temporarily.

 

[Enough Already]

More info would be helpful - is it stalling out at idle speed or full/mid throttle? While throttling up/down? Does it happen after an extended period of trolling? Any alarms when it cuts off?

 

[Tucker]

Flippin' electrical problems are my biggest fear. So this poor guy needs to take it out and run it until it shuts down and then pull out the multimeter. Yep, I'd have to put on the glasses, strattle the rigging, hook up the meter, and try to read it in. I'd probably barf from motion sickness...

 

[seasick]

If the motor starts right up, there isn't much you will find with a multi-meter. I don't think it is an alarm issue either since the motor shuts off and does not go into safe mode.
You only need to drop supply voltage for a brief time for the motor to shut off, so look for loose connections. Start with the main ground at the motor, then look at the main 12 feed, the main fuses in the motor, and the fuses/connections at the helm. It is probably not the Kill Switch since it restarts immediately but it could be. Try wiggling the ignition key, the kill lanyard etc.
I am leaning towards an electrical issue at the motor and not a happy one at that.
One thing about the gauges: If you have the command link gauges, the trip meter resets when the main battery feed ( usually the battery switch) is turned off. If your problem is due to loss of main battery voltage, when you restart the trip meter will read zero. So take a look after the problem occurs.

 

[Aquamist]

The motor shuts down at cruising speed, no alarms go off, it doesnt go into limp mode. I just went fishing yesterday and it only shut off once on the way out and it was ok for the rest of the day. Ill start looking at different connections. Wish me luck!!! I hate electrical problems. Thanks for everyones input

 

[Got Grady?]

Maybe I can help with this. My ox66 was doing the exact same thing and I mean exact. I would be cruising along at 4k rpms and it would just die. It didnt hesitate or stumble just shut off like I turned off the key. It would start back up every time and run fine for awhile but each trip it would do it more often. I kept changing fuel filters added a second fuel filter and it just kept doing it. On a trip a few weeks ago it shut down and I thought oh great this again. The only difference was this time it didnt fire back up after repeated tries I finally called sea tow and they got me back to the ramp safely. I tried it numerous times on the way in and the next day on the hose and nothing. I figured the same thing it must be electrical since it wouldnt start even when pumping the primer bulb. Before I did anything further I sprayed some starting fluid into the intake while my son cranked it over and it fired right up and died when I stopped spraying. Ok so it has to be fuel related. I figured it was time to clean the vst tank anyway so thats where I started. It was spotless inside so I removed the high pressure fuel pump and dried it out and put 12 volts to it....nothing not a peep. I shook it and then turned it upside down and it started running, only when turned upside down. Easy enough its a bad fuel pump. Called around and everbody local wanted $800 plus for the pump. I googled the part number and there was an ebay auction with one for $370 brand new with an 850 area code which is the same as mine. Called the guy and he said he buys them by the case and yes I could come pick one up for that price. Made the trip and got it and also two new low pressure pumps since I had everything apart(read that they should be replaced every couple years and they were original, you can tell by the white tabs of the gasket sticking out cause the new ones have a black gasket). Got it all buttoned back up and it fired right up. I have had it out several times since then and it runs better than ever and has not shut off on me once since. Guess it had a bushing that was going bad and it finally just gave up. It ended up costing me about $470 with all the gaskets and took about an hour to do. Of course this didnt include my gas to drive 60 miles each way to get the pumps and gaskets but I needed the parts asap for a fishing trip that week. Now I cant say this is your problem but it sure sounds the same. Good luck! Oh and I never had any alarms on mine either.

 

[Aquamist]

I replaced the high pressure fuel pump not to long ago(couple months), maybe I got a bad one. Thanks and Happy New Year.

 

[Never Enough]

are your fuel pickups in the same tank? I have had people with items in the tanks that will cause it to be grimlin :hmm

 

[seasick]

I replaced the high pressure fuel pump not to long ago(couple months), maybe I got a bad one. Thanks and Happy New Year.

Very possible that this is a high pressure pump issue. Take a look at the connectors first to make sure they are tight. An intermittent pump is tough to diagnose. The only way I can think of is to have a pressure gauge attached to the output while running and look for pressure drop when the motor dies. Unfortunately that isn't a very practical thing to do at sea. At the dock you could try a gauge while giving the pump housing some decent whacks to see if you replicate the failure. Swapping pumps between motors is an option but that's a lot of work.

 

[Tucker]

Just throwing this out there; could we also have a problem with the HP relief valve relieving wrong?? Bad connection sounds like the real culprid. Guys in my marina with those big 4-strokes always seem to be plauged with loose grounds

 

[Aquamist]

Well, I still haven't found the problem!!! Yamaha is sending a tech out on the water with me in the mourning and even paying for the fuel. Thanks for the help, I'll post back hopefully with good news

 

[Tucker]

Aquamist, start a new thread on this over on the Yamaha forum at boats.net. Some pretty sharp cookies there.