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aeclar1

Sensor Issue? Enging cutting @ speed

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aeclar1

Hello all,

Readind everyones forums have been a great help. My problem has not been completely addressed however. I have a 2001 Sunsetter VLX and I'm having problems when I reach speeds in excess of say 25 mph. Boat starts, runs, intitially accelerates etc just fine. When I am just cruising or try WOT the engine will bog down and make me go to idle. When this process starts, feathering the throttle doesn't make any difference, it basically just shuts down all acceleration capability. So, I let the boat sit at idle for a few minutes, then mayby cruise @ 5mph for a minute then eventually it will let me accelerate again to cruising speeds, but after awhile will just bog again.

I have replaced the Impeller and then rechecked it and it is fine. I have checked the the transmission cooler hose and it is clear of all debris.

Before any of this happened, when I first bought the boat, I took it out and it starting smoking and wouldn't accelerate. I found it to be the impeller that was bad. I changed it that day and since then Ive been having this bogging problem. I'm assuming its a sensor problem. Its almost like the sensor is telling the throttle that the motor is too hot, and shutting it down, when the motor actually probably isn't all that hot.

Any advice? What sensor should I check first?

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ecj

Hello all,

Readind everyones forums have been a great help. My problem has not been completely addressed however. I have a 2001 Sunsetter VLX and I'm having problems when I reach speeds in excess of say 25 mph. Boat starts, runs, intitially accelerates etc just fine. When I am just cruising or try WOT the engine will bog down and make me go to idle. When this process starts, feathering the throttle doesn't make any difference, it basically just shuts down all acceleration capability. So, I let the boat sit at idle for a few minutes, then mayby cruise @ 5mph for a minute then eventually it will let me accelerate again to cruising speeds, but after awhile will just bog again.

I have replaced the Impeller and then rechecked it and it is fine. I have checked the the transmission cooler hose and it is clear of all debris.

Before any of this happened, when I first bought the boat, I took it out and it starting smoking and wouldn't accelerate. I found it to be the impeller that was bad. I changed it that day and since then Ive been having this bogging problem. I'm assuming its a sensor problem. Its almost like the sensor is telling the throttle that the motor is too hot, and shutting it down, when the motor actually probably isn't all that hot.

Any advice? What sensor should I check first?

I'm sure others who know more will chime in, but, what your describing sounds like you are overheating, at least the ECM thinks so. When the ECM detects an overheat it goes into protection mode and cuts off ignition to 1/2 the cylinders, making it bog down and not accellerate. When you said your impeller is fine and working I'm assuming the temp is staying normal? Should be 160 +- a little. The coolent temp sensor sends the signal to the ECM.

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dlb

I would replace the thermostat next. Also you can take the raw waterhose and put it in a bucket full of water and make sure that the draw is correct. It should be around 5 gallons in 15 seconds.

Hope this helps

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Bake's Marine

Questions and comments

  1. Did you remove all the impeller debris from your cooling system? It gets packed at the transmission oil cooler
  2. What is your engine operating temp?
  3. When is the last time you changed your fuel filter(s) (your boat may have two)

- Paul

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Pappy

Had a very similar thing happen to me last season. My boat would be running just fine and then it would sound like it was drowning in fuel (deep bog sound). My boat did not have any cooling issues and from what I read in your post the boat is doing this while the temperature is still good. My problem ended being the little screen filter on the inlet of the fuel pump was clogged. The boat never did it again. Hope it helps.

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JasonK

i recommend running the boat out of the water on a fake a lake. stay in it, watch your temp gauge, idle it for a good 10 minutes and see if the temp gauge acts normal (up and down ~10 deg. with thermostat acting normal). If it goes well, drop it right in (while still warmed up)and run it at high idle while docked. How long does it take to overheat (get above normal temp)? Is it right away? Takes some time?

I think you've got old impeller plugging something. did you remove the trans cooler?

Does it bog out before the temp gauge gets to normal temp?

Maybe try draining the block and see what comes out.

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