what *causes* a rectifier to fail?

[gooloo]

60hp yamaha 2stroke, early 90's model.

i'm 90% sure the rectifier has died.... going to pull it off and test it this afternoon.

assuming it has failed..... what's to stop a replacement failing again? (straight away i mean, not in a few years time) is there something i should be checking that could cause it to fail? an over voltage from somewhere? bad connection? anything?

or do they just blow for their own reasons and a replacement will solve the problem?

[TheRealAndy]

Two things, overload and transient damage. The latter is inevitable in that environment and is most likley the reason.

[finga]

Heat and crook connections....and they live on an outboard.
The latter seems to be a common reason to fail.

[cormorant]

Switching battery switch off or on when motor is running will do it or between batterys in 2 battery set ups when running motor or having a battery that has dropped a cell. Voltage regs on larger caoacity outboards have a heatsink that is cooled by water in the leg so poor impellers can stuff them.

Overloading them with too larger battery or too smaller battery and resistance created by bad teminations or corrosion.

Overloading electrical capacity of alternator combination can fry them as well

[Gon Fishun]

Ah ha it is a rectal thing.