Rexx

If you suspect a temp sensor, unplug the dang thing while it is on the hose, then short the connector out to track similar behavior. Sorry, but replacing parts is tax on people bad at solving problems methodically.

johnfharding

Running fine on the hose as compared to in the water. Is that in the water in neutral compared to on the trailer in neutral? That is the way I took it. I wouldn't think electronics woud have much to do with it as the thermostat would still control the water temp at the sensor location regardless of water source. Is this a single engine boat? I'm thinking water in the fuel. I say this because if you throw out all the electronic sensor stuff. You guys are all over that like a hound on dinner. The only thing that may have changed is the orientation of the boat to level as compared to that of being in the water. Water will find its way to the lowest point which could be different or more spread out on the trailer. Hince the fuel pickup may not always be getting the water.

Big Boys Toys

You did say earlier you changed out the water seperators, did you dump them into a clear glass and see if there was water contamination. A little water goes a long way! Will run, then backfire, then run good and then run ****ty. Post your findings, we are all interested!

sonicss42

"OBNOXUS" from anther site was the first to respond with the closest answer to the problem. The scan tool was definately needed to find that the ECU was not getting the proper signal from the coolant temp sensor even though it was new. Another gremlin turned out to be related wiring as in part #84-817376T which is the wiring harness from the distributor to the coil. Thanks to all whom pitched in their ideas and theories as I tried most of them. A special thanks goes to Tony from Chesapeake Marine Service here in Middle River for his experience and guidance during this troubleshooting.