I’m an idiot!!!!!!

[Cmb0034]

I unfortunately switched battery cables today and didn’t realize it fast enough. Johnson 28 special. Saw a bit of smoke and then nothing. What did I do? Blow a fuse? How may does this motor have, where? HELP

 

[Vic.S]

You don't say what year or give the model number but you should be able to locate a manual , which will include wiring diagrams, at http://162.144.28.33/
This should help you locate the fuses but I suspect you have blown the rectifier.

You can test the rectifier following Joe Reeves instructions on the Engine FAQs board, but if you do, either use an analog meter ( Joe's preference! ) or the "diode test" setting on a digital meter.
Alternatively see the CDI Electronics' on line "Troubleshooting Guide" at http://www.cdielectronics.com/wp-content/uploads/2013/02/CDI Troubleshooting Guide - 2012.pdf

 

[F_R]

Reverse connection of the battery cables is just about guaranteed to blow the rectifier. You can't disconnect them fast enough to prevent it. But the motor should still run after correcting the cables. Are you saying it doesn't?

The alternator won't charge the battery if the rectifier is blown.

 

[Cmb0034]

Yes, it wouldnt do anything even after the cables were switched.

 

[Cmb0034]

Model is Johnson 28 Special E28ELCDC

 

[racerone]

The 28 hp motors show one fuse at 20 amps.----Find it in the wiring near the solenoid.-----~ 5/8" long.

 

[Chinewalker]

You probably did two things - let the smoke out of the rectifier, and blew the starting circuit fuse. Both are easy enough to check, replace as needed.

 

[Cmb0034]

Alright so i replaced the rectifier, fuse looks good....still nothing, won't turn over.

On the rectifier, it had three yellow wires and one red. I did my best to position the yellow wires as they were in the old part but the jelly like stuff in it made it hard to see where they were situated. Does that matter or as long as the red is where it should be we are good?

So a bit of history on this thing. I have had the carb rebuilt and fuel pump replaced, both by a mechanic. But last time I took it out it wouldn't do a thing, I thought because I swapped the battery cables, sure this is part of the problem but what else could it be?

 

[Crosbyman]

apply batt +12v directly to the starter red post connected to the selenoid .. if it won't crank work backwards


now apply 12v directly to the selenoid control post connected to the start key wire
if the starter cranks work backwards

go to the start key and apply 12v to the control wire connected to the selenoid if it cranks work backwards

find out why the start key does not apply 12v to the "start control post/wire" going to the selenoid

the start key assembly should have 12v coming to it from the bat if not find out why (another fuse maybe, a switch ??0

you must have 12v ready to be routed to the selenoid from the start key

 

[Cmb0034]

Thanks Crosbyman! I'll check it out.

 

[Cmb0034]

Also does the placement of the yellow wires matter on the rectifier?

 

[oldboat1]

Match up stripes if the new rectifier has them, otherwise just yellow to yellow. Red wire to red wire.

 

[Crosbyman]

apply batt +12v directly to the starter red post connected to the selenoid .. if it won't crank work backwards


now apply 12v directly to the selenoid control post connected to the start key wire
if the starter cranks work backwards

go to the start key and apply 12v to the control wire connected to the selenoid if it cranks work backwards

find out why the start key does not apply 12v to the "start control post/wire" going to the selenoid

the start key assembly should have 12v coming to it from the bat if not find out why (another fuse maybe, a switch ??0

you must have 12v ready to be routed to the selenoid from the start key

big type error on my part ​

:facepalm:

CORRECTION...!!! applying 12v to the starter main +12 post should spin it... make sur it does if it does not bad starter or ground

then work backwards if it does btw some engines have safety interrupts try and get a wiring diagram

 

[Crosbyman]

if I have the correct diagram that selenoid ground side gets it's ground via a cut-out safety switch and a mercury switch make certain the GROUND side of the selenoid is grounded (ready to start) when applying +12 to the control post otherwise the selenoid won't pull up to engage the starter with 12v from the batt.

 

[Cmb0034]

There's a decent size red rubber boot that looks like it can be pulled apart. What might that be?

 

[Cmb0034]

[No message]

 

[89retta]

That is just where your control plugs into the harness on the engine.

 

[5150abf]

You mean THE BIG RED PLUG, connection between the boat harness and the engine.

Have you tried jumping the starter,directly, sorta sounds like that may be the issue, worth confirming it works or not before you tear into to too much.

Oh and I will bet almost everyone on the boards has hooked up cables backwards, probably multiple times for myself.

 

[oldboat1]

...and one of the side effects of reversing polarity is a blown rectifier (as mentioned above).

 

[Cmb0034]

Ok so I have replaced rectifier and starter solenoid. I have power going to the solenoid but not on the out side of solenoid or either top terminal. I have made sure the power plug is tight. Fuse looks good, starter does indeed jump. What else???? About to drill holes in the boat and sail it!