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450hp@bellsouth.net
10-08-2012, 08:36 AM
2000 Prostar 205v overheated on Saturday. I was towed in and started to diagnose. Impeller and water pump are good. All water lines are clear. I flushed the filter inside the transmission cooler. I then removed the thermostat for a test and it ran cool at about 140 degrees. Picking up new thermostat today.

All seemed fine until I gradually accelerated to 4K rpms and then the tach would start to dance up and down and the motor would shake a bit. Tried some Staybil in case gas had some water but no luck. My guess is fuel pump but not sure if running lean would cause the iniital overheat? Runs fine under 4k RPM.

Always tougher to fix if multiple problems occur on same run. Any theories or ideas would be appreciated!

Barry

JimN
10-08-2012, 09:12 AM
2000 Prostar 205v overheated on Saturday. I was towed in and started to diagnose. Impeller and water pump are good. All water lines are clear. I flushed the filter inside the transmission cooler. I then removed the thermostat for a test and it ran cool at about 140 degrees. Picking up new thermostat today.

All seemed fine until I gradually accelerated to 4K rpms and then the tach would start to dance up and down and the motor would shake a bit. Tried some Staybil in case gas had some water but no luck. My guess is fuel pump but not sure if running lean would cause the iniital overheat? Runs fine under 4k RPM.

Always tougher to fix if multiple problems occur on same run. Any theories or ideas would be appreciated!

Barry

StaBil won't do anything for gas that has water in it. Shaking isn't usually a symptom of a bad fuel pump, it's either RPM reduction (the injectors or banks of injectors are toggled to keep the engine cooler by intermittently stopping combustion), bad coil pack or interruption of the signal that causes the coils to discharge spark.

What happened immediately before it overheated? Did you beach it or stop on a sand bar? Is it possible that a plastic bag was sucked into the grate?

How old is the impeller?

450hp@bellsouth.net
10-08-2012, 09:30 AM
Jim,

Thanks for the quick reply.

I replace the impeller every year when I winterize. The one I took out / replaced this weekend was less than a year old and had maybe 50 hours on it.

Before the overheat I pulled the boat off the lift and had to jump the battery as I had not started the boat in over a month. I let the boat idle for several minutes to charge and all was fine (Temp, oil pressure, etc.) We were on flat water going about 45 mph when the motor sputtered and eventually stopped.

Once on the trailer I looked to see if there was a plug in any of the water lines and all were clear. Sounds like you are thinking something electrical.

barry

JimN
10-08-2012, 09:38 AM
Jim,

Thanks for the quick reply.

I replace the impeller every year when I winterize. The one I took out / replaced this weekend was less than a year old and had maybe 50 hours on it.

Before the overheat I pulled the boat off the lift and had to jump the battery as I had not started the boat in over a month. I let the boat idle for several minutes to charge and all was fine (Temp, oil pressure, etc.) We were on flat water going about 45 mph when the motor sputtered and eventually stopped.

Once on the trailer I looked to see if there was a plug in any of the water lines and all were clear. Sounds like you are thinking something electrical.

barry

Make sure the battery cables and clamps are clean and tight at the battery.