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4108 not charging


dhoadley

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My 4108 (model #1690261) isn't charging. I checked the regulator for resistance at the field and it was fine. (I read that this morning when I did a search on this problem) I checked for voltage at the little fuse on the side of the engine and have nothing. The engine is a Briggs 191707 0686-01. It doesn't have an S/G, is that wire with the fuse inline where the charge should be coming from? I'm pretty hopeless with electrical problems. If not for this site, I'd probably have to pay-the-man. Thanx, Dave

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By the starter, my guess is that you have two wires going into a plug, a red and black. The red is a DC circuit and should meter out at least 12 DC when running and the black at 12 v AC. If you get those two values you charge and light circuits work and now you can progress forward to find youe problem.

5/24/15- Looked up operators book and it has wire diagram and it just shows a red wire coming out as a charge wire going to ignition switch. You might have loose or dirty connections around ignition switch.

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I have one wire coming from behind the starter, which I would call brown but may have been red at one time. It has a fuse in line and goes into the wire harness.

P5230727.JPG

I have a multimeter that I barely know how to use and I get nothing at the brown/red wire when running. Thanx, Dave

P5230727.JPG.d24b6596370c275af27e5aee7165a207.JPG

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Turn your meter on and then to DC. With engine running, stick one meter probe into the yellow connector and then the other probe to the engine block. You should read + or - 10 to 13.5 volts. That tells you that the generator has a charge voltage.

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Also I forgot, if you have an analog meter switched to DC, it might peg to zero. If that happens, just turn the leads around and test again.

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quote:Originally posted by BLT

Also I forgot, if you have an analog meter switched to DC, it might peg to zero. If that happens, just turn the leads around and test again.


id="quote">
id="quote">It is an old one with a needle that swings across. I'll keep that in mind. Thanx, Dave
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I tested before the fuse and that wire is dead. No reading, no way. Where does the charging come from on these engines? The coil where the spark plug wire comes from? Thanx, Dave

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Is that thing that has black tape on it the fuse? If that is the case, move the off the tape, then take a reading off the brown wire a see what happens.

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quote:Originally posted by BLT

Is that thing that has black tape on it the fuse? If that is the case, move the off the tape, then take a reading off the brown wire a see what happens.


id="quote">
id="quote">That is what I did earlier today. The wire is dead at that point.
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Originally posted by dhoadley
quote:
id="quote">Then you have to lift the blower housing to see if there is a broken wire.
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I dug into it this weekend. Took the flywheel off and was looking at this.

P6050732.JPG

I've had the flywheel off before chasing a no spark issue, but never noticed this. I saw what looked to me to be the end of the winding at the phillips head screw on the right, so I checked continuity between that and the fuse and it was good. The magnet surface facing the flywheel looked to have a little surface rust so I took a little emery cloth to it and cleaned it up. I put the flywheel back on and started it up. Nothing at the fuse. 12v at the battery at low rpm drops to 11v at WOT. The only thing I can think of is that I lost the diode or whatever that little electrical thingy was by the fuse. I was told in another post that I needed that to keep the electricity flowing in one direction, so I replaced it with one from Radio Shack (RIP). Could I have wired it in backwards or gotten a wrong value? Thanx in advance, Dave

P6050732.JPG.f4616d99124c7106f969bd657f9a3ced.JPG

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So, with no further input, I'm going to fall back to my default strategy; start replacing things. Since I'm getting nothing straight from the altenator, I'm thinking of starting there. The engine is model #191707-0686-01. I had a hard time finding a part #, but one site gave me this; PS9066396. $43.+ plus shipping. I found this on Ebay.

http://www.ebay.com/itm/231568431941?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

That looks the same to me. Any suggestions before I make an offer? Thanx, Dave

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Dave,

What was the open circuit A.C. voltage of the alternator output at the brown stator wire @ full throttle (say 3600RPM's)? If above say 14 volts or more, then the stator is OK. The rectifier diode polarity needs to have the cathode end (color band at one end) connected to the B+/battery positive side of the system. You need a diode capable of the full current the stator can put out, so something like a 1N5408 type diode (3 amp rating) or for higher current alternator/stators something like this:

http://www.mouser.com/ProductDetail/Diodes-Incorporated/10A07-T/?qs=sGAEpiMZZMtbRapU8LlZD2cP9o4TI62wnV4jGcIKF0I%3d

These as very cheap components and probably out there on eBay as well. Seeing how the battery voltage is dropping when revving the engine up, says you have the diode(if still present) in backwards and allowing current flow back into the stator.

Tom (PK)

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Tom, There is zero volts at the brown wire @ WOT. I will double check the diode orientation. Thanx, Dave

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  • 3 weeks later...

I picked up an alternator that looked identical from Ebay. $30 NOS with shipping seemed like it was worth a try. This is what I got.

P6180759.JPG

16 hp? oh well, it fits in my 8 hp.This is the two side by side; new to the left, old to the right.

P6180760.JPG

I also checked the diode and the stripe is on the battery side, which I understand to be correct. I used it for half an hour today and the same last weekend. If the battery holds up, I'll call it fixed. Me and my multimeter barely understand one another so I'll be happy with results. It looked like I had 16 volts, but I don't think thats right. Thanx Bob & Tom for your patient input.

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P6180760.JPG.984820ed8f6450383919ecdf3606c7a3.JPG

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Dave, was that 16 volts A.C. at the stator wire (before the diode) or 16 volts D.C. at the band end of the diode and disconnected from the wiring? With a fully charged battery and with the charging system connected & working correctly at full throttle, you should be above 13 volts D.C. at the battery.

Tom (PK)

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Tom, that was at the battery, but I have a 30 year old Radio Shack multi meter with too many settings and options for a guy who doesn't really know what he's doing. I have a tach/dwell meter in the basement (which is even older) that reads volts and I'll check the voltage with that next weekend. All my tractors are at a rental property I have about a mile from my house. Thanx, Dave

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  • 2 weeks later...

Well, I think this case is closed.dOd With the tach/dwell hooked to the battery before startup, 12.0 volts. After startup, 12.2 volts after 30 seconds, 12.3 after another 30 seconds, pushing 12.4 a minute later. Thank you for your support! Dave

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  • 1 month later...

Not so fast! Its not charging. C I've replaced the internal alternator, I have a fresh fuse, the diode has the stripe towards the battery side, and the battery is good. I may have to (gasp) bring this to somebody to fix. Oh, the shame! :I Any other thoughts before I swallow my pride. Thanx, Dave

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I don't know whether to shift this to "Senior Moments" or just accept that I'm the world's worst electronic diagnostician.:I Decided to put a fully charged battery in and start again. Start the engine and tested the wire coming out of the engine. 16 Volts! Hook it back up and test at the battery. 12.2 volts, no charge. Pull the fuse and test again at the fuse. 0 volts!! A blown fuse. I hang my head in shame (as I do my victory lap).^ Thanx, Dave

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