electrical

[shenders52]

I have a 60 hp Johnson outboard around1990 model I hooked the battery terminals backwards everything works trim,jackplate ,lights, but try turning it over and nothing it on a 1990 Carolina skiff (help)!!!!!!!!!!

 

[JimS123]

You blew a fuse. Look at the owner's manual to find out where it is. If you don't have one, get one.

(I assume you hooked it up correctly after you found the problem).

 

[oldboat1]

Check tach and/or charging system when you get it running.

 

[oldboat1]

https://maxrules.com/graphics/omc/wiring/78-84_3-CYL_EL.jpg A little older, but believe the fuse is in the hot wire coming off the large solenoid post. If you reversed polarity, you may have burned out the rectifier, which would likely affect both battery charging and tach operation.

 

[Crosbyman]

does anyone know why boat rectifiers blow all the time when their batt. polarity is reversed ... ??

typically, a diode's role in life is to control the direction of current and block reversing voltages ... like rectifying AC voltages in power supplies.

 

[Faztbullet]

Got to be something about the diodes that are connected to rectifier case

 

[F_R]

In normal operation, the diodes block the battery from discharging through the alternator. Reverse the battery, and current almost free-flows back through the alternator, at a high amperage rate, higher than the diodes can stand, so they burn out.

 

[Crosbyman]

that would imply current flow against the directional control properties
of the diodes...

I have a few spare 25 amp 4w bridges.... time permitting * i'll try and blow one


* between my real duties

 

[F_R]

In simple terms, if you connect a plain wire across the terminals of a 12V battery, it will get red hot and burn in two. Insert a diode in the wire in a direction that it blocks the flow, then no current flow, no heat, and everything survives. However, if you insert the diode in a direction that it does not block the flow, you are right back to the same thing as a wire with no diode---it burns up at the weakest point (the diode)..

 

[racerone]

^^^^---Applause and more applause on post #9 here.

 

[Crosbyman]

gee.. that felt good saves me a 25 amp bridge

 

[JimS123]

I thought that modern OBs and RVs had a fuse that would protect the sensitive circuitry if the battery were hooked up backwards. It was supposed to blow before any other component.

 

[Scott Danforth]

clean all the battery cable connections from the battery to the slave relay to the starter. also pull the starter and clean the mating surface of the block and starter (ground path) been more than one johnyrude that wouldnt turn over from corrosion on the starter mating surface.

 

[F_R]

I thought that modern OBs and RVs had a fuse that would protect the sensitive circuitry if the battery were hooked up backwards. It was supposed to blow before any other component.

Can't speak for all "modern" outboards, but for the vast majority, if not all, the charging circuit is not fused.

 

[PhilSch]

I think you blew the powerpack