I have a 02 380 sundancer . When...
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06-27-2016 10:56 AM
I have a 02 380 sundancer . When fuel tank goes below 1/3 full on starboard side the starboard engine will lose rpm at speed . Marinemax guy said he thought starboard fuel pump going out . Although it didn't do it when he came for ride w me . Any suggestions ?
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06-27-2016 03:09 PM
Has the fuel pressure been monitored at the fuel rail w/ a gauge?
There are fuel cutoff solenoids, one for each engine and one for the generator.
The fuel cutoff solenoids used on mine have an electrical enable and also have a twist knob.
The logic on the twist knob on the solenoids used on my boat are: fuel flow only when electrically activated or always on.
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06-27-2016 04:00 PM
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06-27-2016 04:55 PM
It might be that the problem does not directly correlate to the fuel level. That would not be my first guess.
The invaluable tool required for the arsenal is a fuel pressure gauge. The engine won't go w/o fuel pressure.
The usage is "easy". It screws onto a standard Schrader valve, like on a bicycle, on the fuel rail feeding the injectors. The main concern is that fuel is very flammable, so connecting / disconnecting / usage needs to be done w/ appropriate care, especially on top of a hot engine and in a closed compartment.
There is negligible difference between sucking from a full tank and one w/ 1/3 gone.
The other suspect is a poor electrical connection on the fuel shutoff solenoids. They are on the forward wall of the engine compartment. How do the electrical connections look at that point?
Assuming your Parker / Skinner fuel solenoids are like mine, then try operating the engines w/ the twist valve arrow pointed to the left, to off, so it provides fuel only under electrical control. Then if there is a problem, twist the knob to the right, to on, so it always provides fuel. The normal default operation should always be w/ the arrow to the left.
Otherwise treat the boat like a patient, "it hurts when I do that", "don't do that".
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06-27-2016 05:42 PM
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06-27-2016 05:45 PM
The Mercruiser implementation is very poor and these require periodic maintenance for proper operation.
My hope is the engineers who "designed" that system on my earlier engine were retired before they had a chance to duplicate it on yours.
The engines require sufficient fuel pressure, especially at speed, to maintain proper rpm / power.
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06-27-2016 05:51 PM
Then after topping off both tanks change both fuel filters.
All 16 of my injectors were sent out for cleaning and testing. They found problems that required some to be replaced. It was well worth the cost and effort!
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06-28-2016 06:16 AM
The two engines are completely independent. Each has it's own ECU, it's own fuel supply and it's own electrical supply.
The most common way one engine can affect the other is that when an engine's output drops significantly, such as pulling back one throttle while on a plane, the rpm of the other engine will drop. The boat is designed for both engines to rotate at the same speed. The engines cannot / will not maintain rpm if one engine drops out.
It is most likely that the problem is related to one engine.
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06-29-2016 11:29 AM
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06-29-2016 01:04 PM
If there is a problem while pointed to off that is eliminated while pointing to on, then either the valve is bad, or the electrical signal controlling the valve is bad.
Where were they pointed up until now?
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06-29-2016 01:05 PM
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06-29-2016 06:30 PM
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06-29-2016 09:11 PM
If there is no effect on correcting the problem, then the fuel cutoff solenoids are not the problem and they may be returned to the OFF position. Normal / safe operation is w/ all three solenoids in OFF position.
Ensure the electrical connections are tight and secure, both the nuts retaining the ring tongue connectors to the solenoids and the ring tongue crimp to the wire.
My guess is still a fuel problem, like: dirty fuel (fix by running tanks very low and adding cleaner / dryer, running some more, topping off tanks and changing fuel filters); insufficient fuel pressure (maybe bad pump or fuel pressure regulator problem, monitor fuel rail pressure before and during problem), or bad / dirty fuel injectors (check electrical connections (16) are secure, send injectors for cleaning / testing).
Good luck!
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06-30-2016 06:54 AM
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06-30-2016 07:58 AM
Keep all three solenoids in the OFF position and move to investigating the other potential issues.
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07-11-2016 06:07 AM
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07-11-2016 06:13 AM
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07-11-2016 07:01 AM
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07-11-2016 07:24 AM
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