please help jhonson electrical problem

[grady white sailfish]

please help i have a 1990 jhonson 200hp looper and its running good but the tach isint working and neither is the volt meter. its not the rectifier because i replaced that twice with brand new ones. if any of you have ideas please post im so frustrated.

 

[wilde1j]

Re: please help jhonson electrical problem

Try measuring the Dc voltage across battery terminals with motor at a fast idle (~ 1200 RPM) and advise the results.

 

[grady white sailfish]

Re: please help jhonson electrical problem

i did an inline amperage check between the rectifier and starter relay and got approxamitly 30 amps. im getting no voltage from the gray wire at the rectifier. what can cause this?

 

[jriegle04]

Re: please help jhonson electrical problem

where is your grey wire attached? is there a terminal block on the motor? is your tach known to be good?

 

[wilde1j]

Re: please help jhonson electrical problem

Measuring across the battery terminals will confirm if you're getting any charging. If you don't get 13.5 VDC or>, no charging is happening ... doesn't make any difference whether you changed the rectifier 2X.

Do you know what the grey wire is used for? Typically it's the tach + lead and will have 12 VDC pulses on it. May not necessarily read on most voltmeters.

 

[grady white sailfish]

Re: please help jhonson electrical problem

the wire is at terminal strip at back of motor under powerpack and it comes from the rectifier. and yes i think the tach is good because if we jump voltage to this terminal then tach works.

 

[jriegle04]

Re: please help jhonson electrical problem

are you using a 35amp system with a water cooled rectifier?

 

[grady white sailfish]

Re: please help jhonson electrical problem

yes i am.

 

[jriegle04]

Re: please help jhonson electrical problem

according to what i have learned from here, if you can take you grey tach wire from the terminal strip that runs to the wiring harness and attach it to the yellow wire with grey stripe and the tach works that means that the regulator / rectifier is bad.

 

[jriegle04]

Re: please help jhonson electrical problem

another word of caution is those water cooled regulator / rectifiers have been known to catch fire from overheating. i have the same setup and am having the same problems. but with mine the tach isn't working either way.

 

[grady white sailfish]

Re: please help jhonson electrical problem

i will check it this way but what would cause the rectifier to go bad?

 

[jriegle04]

Re: please help jhonson electrical problem

a short in the wires for the rectifier or possibly something going on with your stator. is there a brown or black colored goop dripping down the engine block from under the stator or flywheel?

 

[wilde1j]

Re: please help jhonson electrical problem

according to what i have learned from here, if you can take you grey tach wire from the terminal strip that runs to the wiring harness and attach it to the yellow wire with grey stripe and the tach works that means that the regulator / rectifier is bad.

Don't do this! The yellows are AC voltage from the stator and you sure don't want the tach plus lead connected to that! You may be buying a new tach!

As I suggested above, measure the DC voltage across the battery terminals to confirm if charging is occurring. If not, the measure AC voltage across the yellows to the rectifier. If +>30 VAC, the stator is OK. Otherwise the stator is fried and needs to be replaced.

 

[grady white sailfish]

Re: please help jhonson electrical problem

i just put a new stator on and there is no goop dripping. after i check the tach with the gray wire to the yellow i guess i will have to check rectifier?

 

[grady white sailfish]

Re: please help jhonson electrical problem

is it possible for the rectifier to allow battery charge and still not have volts to the tach?

 

[jriegle04]

Re: please help jhonson electrical problem

http://forums.iboats.com/showthread.php?t=190636 read that and see what you think you should do....

 

[wilde1j]

Re: please help jhonson electrical problem

I stand corrected. Joe Reeves knows. You can still do the two very simple tests I outlined above to see if charging is happening and the stator AC output is good.