What makes a Stator go bad? and once i replace it will this happen again?

[mikemartyo]

I just bought a 77 crestliner apollo 660 - nice enough boat, it has a Johnson 77 85hp on it.<br />we were out this weekend and stopped for lunch - never started again. I have a manual, my dad and i trouble shot and removed the flywheel (after fabricating a wheel puller) and the stator is cooked - one section is melted and the green plastic is smeared all around the inside of the flywheel. So I know how to replace the stator - but what caused this? just age? i know it is 25 yrs old, but is there some underlying factor that i should fix too?<br />any assistance will be good - since the best price i can find is $240 i only want to do this one time.<br />Mike

 

[Scaaty]

Re: What makes a Stator go bad? and once i replace it will this happen again?

Usually a internal short from age, so all you can do is replace it, but make sure all connections are clean on the rest of the componets

 

[seahorse5]

Re: What makes a Stator go bad? and once i replace it will this happen again?

A stator can also be damaged from a malfunctioning charging system. If your rectifier assembly is bad, or if you have wing nuts on your battery instead of lock nuts,that could be a factor.

 

[cp]

Re: What makes a Stator go bad? and once i replace it will this happen again?

A properly designed and properly built stator should last forever. To understand why some stators don't last forever, look at some of the things contributing to a properly designed and properly built stator. Important things are that the stator design uses wire large enough to carry the intended current, has insulation able to withstand expected voltages, and that the wire insulation be able to stand the heat from both the amps passing through it and from the engine in any environment. The stator must be built without damage to the wire insulation, tightly wound so that the windings do not become loose and suffer mechanical damage, with magnetic steel that does not create hot spots, and good quality connections must be made.<br /><br />So, mechanical damage will cause a stator to fail. The very high heat caused by prolonged excessive amps will cause near term failure. A short circuit may melt both the insulation and the wires. A high voltage spike may cause insulation failure.<br /><br />Michael O - Buy a replacement from a reputable manufacturer and you should get a properly designed and properly built stator. Make sure the replacement is rated for the expected amp load. Make sure when you install it that nothing will hit it when the engine is running. Make sure that your rectifier is working properly and has no shorted diodes so as not to overload the stator. Check to make sure there are no blown fuses indicating a shorted load. Make sure the stator is connected to your battery whenever the engine is running. And if you have a regulator and rotating field winding, make sure it's working properly. Then you should be good to go.