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140 I/O Mercruiser Motor Surging

Troy5050

New member
My v-6 motor runs great most of the time. But every once in a while when running at our cursing speed 3 thousand RPM the motor will drop 3 to 4 hundred RPM & then in a couple of seconds it will come right back up with-out touching the throttle. Then we might be running for 20 to 30 before it does it again. I've changed fuel filter & checked fuel pressure. :confused:
 
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My v-6 motor runs great most of the time. But every once in a while when running at our cursing speed 3 thousand RPM the motor will drop 3 to 4 hundred RPM & then in a couple of seconds it will come right back up with-out touching the throttle. Then we might be running for 20 to 30 before it does it again. I've changed fuel filter & checked fuel pressure. :confused:
 
140 I/O Mercruiser Motor Surging

since this is very infrequent and lasts for a very short time check those plug wires ..make sure they have the proper resistance fit correctly on plugs...check plugs , color condition should all look alike..

fuel problems would be more frequent, last longer on engine dying and reving back up...

still possible fuel/carb has problems...
 
Thanks Cat I can check the plugs Ok, Not for sure how to check wire???

using a volt/ohmmeter you check for resistance. most boat engine use low resistance wire. if the resistance is in the tens of thousands of ohms or open [no resistance ] the wire is bad..also wires should all read about the same...make sure no cracks on insulation/no defects on insulation ..

must fit tightly on plugs also..
 
Sorry Guy this was my first post & I made a mistake on the first one. I've tried to delete the first one with no luck Sorry again
 
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