1998 GW Islander, OX66 250. Was out fishing yesterday, total about 3 hours, 18 miles. Got on plane to return back to marina, and engine sputtered, and lost power. I pulled it back to idle, and after a minute it stalled. After 3 attempts, it restarted, when back on plane and sputtered again. Started second time, and got it to slowly cruise at about 1500 RPM for about a minute, then stalled completely, and would not start. Had to be towed in. Fuel bulb is hard, clear filter bowl is full. Let it sit for a couple hours to cool off, will crank but no signs of a light off. As I start troubleshooting today, any suggestions on where to start? Anyone seen this before? Any help is appreciated.
OX66 Troubleshooting Question - HELP!
- Thread starter Patsy Mac
- Start date
Sounds like You are having a fuel restriction in the vst high pressure pump filter. If you put a pressure gage on the Schroeder valve on the vst while the problem is happening, it will tell you what is going on.
Thanks will check pressure, I've read it should be 35 with key turned on, and fuel today for water. Much appreciated.
Should stay around 35 while running on plane also. It is a 1/4 schrader valve to check pressure . Same as on your car tire. Fuel gage at the auto parts store will have the adapter for this valve in the package.
Parthery
GreatGrady Captain
Check the red/yellow wire that comes out the top of the VST. This is power to your fuel pump and should show power when the key is on . If you have power, you can eliminate that and focus on fuel. If no power to that wire, check the main relay (starboard side of the motor - you can find it by following the aforementioned red/yellow wire.) If power into the relay but not out of it, you have found the culprit. That relay drives both the fuel pump and injectors, and is a common failure issue.
Great point. The key turns on the high pressure pump for 3 seconds when the key is first turned on. You can hear it if you listen to the vst and have someone turn on the key at the same time. Then it shuts off until the motor is running. If there is a problem with the relay, you will have no fuel pressure at all at the Schrader valve.
You mentioned the fuel bulb is hard and the clear filter on the engine is full. But, does the bulb STAY hard and the filter stay full - especially when the issue happens?
FYI... the filter bowl shouldn't be "full" - usually it's about 2/3 full.
FYI... the filter bowl shouldn't be "full" - usually it's about 2/3 full.
It sometimes will fill all the way if the ball is pumped a lot. Then it goes to 2/3 after running. I would first drain the filter in the boat and see what you got. If there is a Red water ring in the filter under the hood, make sure it is not floating. The red ring sinks in gas and floats in water.
The first thing that struck me is probably not your problem BUT; You said the clear bowl on the fuel filter was full after it stalled. Normally the bowl is not full but rather about 3/4 full. If it is indeed full, you may have an air leak in the filter. Just to be sure, remove the bowl, check the gasket and reseat making sure it is correctly lined up.
Secondly, if you had bad gas and the motor stalled because of it, I doubt you would have been able to restart.
Try running with the gas cap off to see if the issue is venting
Secondly, if you had bad gas and the motor stalled because of it, I doubt you would have been able to restart.
Try running with the gas cap off to see if the issue is venting
Thanks for all the help. Here is the update, the filter bowl was full only after I pumped the bulb, which stayed hard, normally it is 3/4 as described. Today I checked filters, all clean, no water, red ring was at bottom of bowl before draining and cleaning, and stay there. Then did voltage check at the HP fuel pump. 12V to the pump, pump does not turn with key turned on. Feels like a bad pump.
Parthery
GreatGrady Captain
You are making progress....but before you condemn the pump (and your wallet), check the ground side of the pump as well. That would be the blue wire coming out of the top of the VST.
If the pump jammed up it may be able to be cleaned and fixed. To free it up, hook it up to a battery on the bench n switch the pos and neg back n forth. Don’t run it more than a few seconds once it is free.
I hope not. That pump is a $900 item.
Is there a resistor inline on that pump? I know there is a resistor for something on SX motors
Is there a resistor inline on that pump? I know there is a resistor for something on SX motors
Omg. It is 900. If you need one, I am sure I can help you find a good used one for a good price.
Appreciate the offer to help find a used one. Will see how checking the ground side works out tomorrow, as well as trying to cycle it on and off to free it up. Thanks for all the great advice all.
I have confirmed that there is a resistor connected to the high pressure pump. I have read posts on other boards about these resistors going bad.
The resistor is in a metal assemble with cooling fins and would be near the VST. It has two wires, Brown and Blue and a connector. When unplugged it should read very low resistance, about 0.55 ohm. I think the issue when they go bad is when they heat up. I honestly do not know how to test it for a temperature problem. It isn't cheap either, about $120 but that a lot less than the pump.
Maybe someone has a spare or old on that you can borrow to test.
The resistor is in a metal assemble with cooling fins and would be near the VST. It has two wires, Brown and Blue and a connector. When unplugged it should read very low resistance, about 0.55 ohm. I think the issue when they go bad is when they heat up. I honestly do not know how to test it for a temperature problem. It isn't cheap either, about $120 but that a lot less than the pump.
Maybe someone has a spare or old on that you can borrow to test.
SkunkBoat
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not an expert but I dealt with ox66 fuel problem. Not exactly same as your problem but...
You seem to be going down the path of 'do it yourself". You will have to open up the VST tank on the path you are on so I suggest do the cheap things first.
Try replacing VST filter AND the filter screen of the pressure regulator. get a new gasket or two...
If you have never replaced them...you need them no matter what.
Here are pix of my pressure reg filter screen
I also replaced VST filter and had injectors cleaned
here's a thread I did on it https://www.greatgrady.com/threads/ox66-225-stumbling-when-running-over-3500-rpm.27657/
Also a couple thoughts;
"...will crank but no signs of a light off"
is VST tank filling/full??
Does it fire with starting spray?
You seem to be going down the path of 'do it yourself". You will have to open up the VST tank on the path you are on so I suggest do the cheap things first.
Try replacing VST filter AND the filter screen of the pressure regulator. get a new gasket or two...
If you have never replaced them...you need them no matter what.
Here are pix of my pressure reg filter screen
I also replaced VST filter and had injectors cleaned
here's a thread I did on it https://www.greatgrady.com/threads/ox66-225-stumbling-when-running-over-3500-rpm.27657/
Also a couple thoughts;
"...will crank but no signs of a light off"
is VST tank filling/full??
Does it fire with starting spray?
