2002 Volvo penta 5.0 Gxi goes to idle during WOT.

[Andan]

I have a 2002 243 Chaparral Sunesta with a Volvo 5.0 Gxi and Sx drive. First trip out on the water this year and I went about 1000 yards after it was on plane at 30 mph and it just goes immediately to idle. It idles fine and never dies. You can wait about 30 seconds and go back to WOT with no issue, but you can only go about 300 yards on plane and it does it again. I’ve changed 3 fuel filters out on it already with no change. I don’t know if I’m getting an alarm before it happens because the alarm isn’t working at start up. (Working on fixing that now ). Any suggestions? All my gauges are reading good oil pressure and water temp.

 

[harringtondav]

I don't know if your carb's float bowl holds enough fuel to last 300 yds, but it might. A bad fuel pump may fill the float bowl when idling, but not keep up when you start using fuel. So my first guess is to check your fuel pump. If electric (?) check the wiring to the pump. Electric pump Mercs have an oil pressure switch that will shut down the fuel pump if the switch is faulty or a low oil pressure condition exists.

 

[alldodge]

GXI is MPI

What's you serial number?
Have you checked fuel pressure?

 

[QBhoy]

Distributor cap would be a good start. If it’s not that, it will save you doing it later.

 

[Andan]

Fuel pressure is fine. Located the problem. The raw sea pump impeller is toast. Found most of the pieces in the hoses and thermostat housing. Is there any other concerns I should be checking into other than making sure the pickup is open through the drive?

 

[alldodge]

All my gauges are reading good oil pressure and water temp.

You were overheating and the motor powered down to save it self. Get your temp gauge fixed and the alarm

They can get in the block and come back out later or in the exhaust. Flushing is about the only way, and if there in the block there probably not coming out. Don't see an issue to run it and this time watch the gauges

 

[Andan]

It looks like the port off the thermostat housing going to the right exhaust was blocked about 75% with impeller pieces. I’m going to guess the sensor on that heat riser **** it down. Does anybody know the wiring schematic for the 3860264 alarm? Not sure I have one on this boat from previous owner. TIA

 

[alldodge]

The alarm always has 12V on one side when key is turned ON. Depending on which GXI the switches and/or ECM places a ground on the other side to turn it ON. Some newer GXI the switches signal tells the ECM and the ECM turns alarm ON

 

[Andan]

This is a GXI-B model number. Best I can come up with is that it is supposed to be located on the plate by the circuit breaker above the engine?

 

[alldodge]

The GXI-B uses a Tan/Black wire on the ground side of the beeper (on the motor) and that wire goes to pin J1-8 on the ECM and also to pin 6 on the 10 pin connector. Pin 4 goes up to the helm and connects to the alarm under the helm