1985 dt140 not charging!

jflat

Cadet
Joined
Feb 7, 2011
Messages
7
Hey all, been at this one for a while. I am the proud owner of a 1985 suzuki dt140 it sat for a long time, ive been working on it for quite a while. It runs good, and ive been using it, but it is not charging a battery at all... I have replaced the rectifier, replaced battery cables, replaced stator... and i just don't know enough about the electrical on this motor to think if there is anything else i havn't done. So if anyone out there has some experience with an issue like this i am all ears and appreciate whatever help i can get thanks.
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
9,247
Re: 1985 dt140 not charging!

Have you tested anything or have you just been replacing parts and hoping?

Do you have a repair/service manual for your motor?
It should have the steps and specs for testing charging system, along with what equipment to test with.
 

jflat

Cadet
Joined
Feb 7, 2011
Messages
7
Re: 1985 dt140 not charging!

I have visually inspected all the wiring as best i can, The old rectifier had a burnt spot and was in pretty sad shape, I havn't tested the stator(s) yet only because i picked up a used one for a good price so i was kind of hoping on that part haha. It's kinda cold here, but i guess i will test the new rectifier, and the stator's to see what i can come up with... I have the clymer manual, and should be able to perform all the tests without too much of a headache... hopefully.
 

jflat

Cadet
Joined
Feb 7, 2011
Messages
7
Re: 1985 dt140 not charging!

I have tested everything about every way possible. stator tests good with amp output, also tests fine with resistance ohm testing, rectifier tests good between all the diodes. I have fairly thoroughly traced through all the wiring, visually inspected all the wiring possible, and most importantly i believe i have sat staring and scratching my head for well over the allotted amount of time. And end result is... at idle battery reads 12 volts, with throttle battery reads 13 maybe a little over but not much, any load on the battery besides engine and volt reading goes way down. When testing dc volts directly out of rectifier at idle it's about 9 volts, however increases very high with the throttle 20+ dc volts. Don't know what significance that is but it's info i suppose. That's about where i'm at anymore help would be greatly appreciated. Thank you
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
9,247
Re: 1985 dt140 not charging!

what do you mean by stator tests good with amp output?

What does the manual call for voltage wise at the different RPMs?what did you get at those RPMs
My C40 yamaha calls for
9v at cranking
25v @1500
25v @3500
And what type of test equipment does it call for? what are you using?
My C40 yamaha calls for a peak reading meter.

What are the ohm reading for both stators and what are the specs in manual?

Just saying they are good does not mean a lot without the numbers and specs as I do not have that info.
 

jflat

Cadet
Joined
Feb 7, 2011
Messages
7
Re: 1985 dt140 not charging!

In book clymer outboard shop manual, at 5000 rpm charging coil should put out at least 6 amps, i got 6 amps at 5000 rpm. my charging coil is located on my stator, i cannot replace charging coils separately charging coil bad = stator bad. sorry for the confusion. you must have a heck of a battery if your motor is pumping out 25v @ 1500rpm my 12v battery would fry. book says to use a self powered test lamp to check one way current through the different diodes of the rectifier, i did not use a test lamp, i checked the continuity which tested fine, current one way but not the other on the yellow and white leads, red and white, black and red and yellow and black. I do not have a separate voltage regulator, my motor only has a rectifier. when testing the charging coil resistance (stator) for the low speed check i got a reading of 654ohms book says between 600-900 is standard, on high speed i read 130ohms book says between 100-150 is standard. These are the tests that my book has for the charging system, all of the tests i conducted received satisfactory results when compared to the standards in the book. I was using a fluke voltmeter which also reads amps, and continuity, book says this method of testing may not be as good as using test specific suzuki issue equipment $ for them, but will work. If i may be missing anything that your noticing let me know.
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
9,247
Re: 1985 dt140 not charging!

No, the readings I showed were for the coil side of rectifier not the line to the battery. Even though it is AC my book calls for reading on DC with a DVA adapter or special peak voltmeter.
That is why I was asking about the specs and equipment.
If you get the amps out but not at the proper voltage then it will not keep battery volts where it should.
On some motors, not sure about yours, there are low speed and high speed charge coils for the ignition system. They charge the capacitors for firing the coils. Make sure you are measuring the proper coils for battery charging.
My Yam manual calls it a lighting coil feeding the rectifier/regulator for battery charging system.


You stated "When testing dc volts directly out of rectifier at idle it's about 9 volts, however increases very high with the throttle 20+ dc volts." was that with it hooked in to the battery or disconnected?
 

jflat

Cadet
Joined
Feb 7, 2011
Messages
7
Re: 1985 dt140 not charging!

Yeah my engine has a high and low speed charging coil all part of the stator. And the 20+ dc volts was directly out of the rectifier NOT hooked to the battery. once i hooked it back up it did nothing? however here is something that is confusing me a bit. I have changed batteries several times throughout this process just to cover my back and make sure nothing was wrong, well i was using the smaller size deep cycle battery (car sized not sure what specific name is) for the heck of it i switched to the larger deep cycle size, like on camp trailers or whatnot and it seems to charge those just fine... 13-14 vlts at idle, and right up to 15 with rpm increase...? i could be retarded lol but i really am not sure what the deal is. have any idea?
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
9,247
Re: 1985 dt140 not charging!

Connections or battery bad is my only thoughts at this point.

Did you understand what i was saying about the high and low speed charge coils?
 

jflat

Cadet
Joined
Feb 7, 2011
Messages
7
Re: 1985 dt140 not charging!

Yeah, i'll do some more checking into the batteries, my connections are all pretty clean, but i'll give everything the look over again and try to clean things up a bit. I'll let ya know if i find anything else out. Thanks for your help.
 
Top