OutdoorKing Repair Forum Forums Repairs and Maintenance Questions On Ride On Mowers Questions On Cox Ride On Mower Frames Briggs 11.5hp charging issue on cox stockman

G,day. Just got a cox stockman. Has a new battery. Though ide put a volt meter accords the battery and check the voltage - no change in voltage with mower stopped or running so am assuming charging circuit not working? Any other tests I can do and possible solutions?

Many thanks?

Is your Stockman a model 4398H? If it is, it would look like this:



Please post a picture of your mower, its model number, and all of the numbers stamped on the cowl of the Briggs engine. Then we can look for a wiring diagram for it, and work through the issues step by step.

Yep that's the one it's got a single red stator wire with diode trying to figure out which part isn't working? If its the diode can they be replaced or does it come with stator only?
Thanks in advance

Oops just read last bit of your reply

Can,t upload photo sorry but its the same model as what you said

Engine details are

Model. 28d707. Type 1148-e1. Code 000504zd

Cheers
Matt

Matt, I can't find any record at Briggs of that model and type, and without pictures I don't believe we will get anywhere identifying your alternator. Sorry, can't help.

Cheers thanks anyway. I rang the local mower guy and explained my problem. He said in 35 years he's not had to replace an alternator on a briggs it's always been the diode. Available from [Censored] smiths. Wouldn't,t tell me what type of diode though. Anyone know what to replace diode with?

Cheers

Briggs alternators vary in output from 1 amp up to about 15 amps, depending on alternator model. The diode has to be rated for at least the alternator's rated current output. Mechanical design is also important - a 15 amp diode will have to dissipate 10 Watts at maximum current, which requires that it be bolted to a decent heat sink. So, first you have to find out the alternator's current output, and look at the mechanical design of the existing diode. If it is only a 1 amp alternator, chances are the diode will just be a tiny black cylinder incorporated in the output wire and will dissipate heat through the connecting wires - it will not be bolted down. See why pictures are needed to resolve any of this?

Yeah that's the one - a single red wire with w small black cylinder built into the wire just before the connector. I,m guessing to check the alternator I might put a small cut in wire between diode and stator stick multimeter probe in and see if I,m getting ac voltage?

If it has a diode in the wire, I expect that will be a low current alternator. The mower's wiring diagram shows two black wires out of the alternator, going to a plastic connector block. It shows one red wire coming out of the connector on the mower side. The other wire from the engine would carry unrectified alternator output (i.e., A.C current) for the headlight circuit if there is one. I expect that the diode will be in one of the engine-out wires, on the engine side of the connector:



If the wiring diagram were correct, the diode would normally be in the black wire that is connected to the red wire, not the unused (AC) black wire.

Unfortunately, you say that there is only one wire coming out of the alternator, and it is red. This would mean your engine is not the one shown on the diagram. It sounds as if you have the Figure 6 alternator:



If you have this alternator, the diode is in the back of the engine side of the connector plug that attaches to the matching socket on the mower side of the connector. If that diode is defective, you must replace it with one of at least 3 amps rating, preferably a bit more. If you get it from an electrical shop it will probably cost you between $1 and $2. If you buy one as a Briggs spare it will probably cost a bit more, but will be genuine. I agree you can test it by checking for AC voltage upstream of the diode, and DC voltage downstream of it, when it is disconnected from the mower wiring. Obviously when it is connected to the mower, there will be DC voltage on it from the battery, whether the engine is running or not.

At the moment I don't know why you are so convinced the diode is faulty.

G,day. Yeah it's the one in figure 6. Will run the tests tomorrow. The diode would be the weakest link and is probably frazzled. Besides I can,t afford a new stator! Am trying to get a diode and wire from outdoorking

I doubt the stator will be at fault (unless it has been damaged mechanically or by a rather sustained and brutal short circuit), but there is still the red wire from the connector to the starter solendoid that could have a problem. I may be unduly cynical, but from the cases I see here at Outdoorking, many second-hand ride-ons come pre-equipped with wiring that has been burned out, ripped out, or revised in a seemingly whimsical manner by a previous tenant. Based on that, I would guess that adulterated wiring is more likely than a failed diode. Even if the diode has failed, there is the question of what made it fail, and what other electrical damage was done by the same series of events. Also, you have not made it clear how you did your voltage test when you tried to verify a rise in system voltage when the engine was running.

Anyway, the tests we've discussed should get you as far as finding both the stator and the diode either damaged or undamaged. It will then be time to talk about other possible problems further downstream.

G,day.

Mower is original nothing appears to be altered or tampered with.

Original test - mower full revs about 12.6v dc across battery. Mower stopped same reading.

This morning I disconnected the diode clip and measure voltage post diode at full revs. Got about 14v dc and about 22vac. Reconnected clip measured voltage across battery again. This time am getting a noticeable .2v increase when running/stopped. Maybe clip wasn't,t connected properly?. Anyway I think I should be getting more volts increase? Post diode am getting more ac voltage than dc So maybe diode partially frazzled?. Good thing I suppose at least stator is working?

Apologies about spelling etc my damn iPad can,t figure out how to turn off auto correct

First, the charging system is only rated at 3 Amps at 3,600 rpm. 3 Amps into a not-very-charged car battery isn't going to do a lot in terms of immediate terminal voltage, so I don't think your original test proved that there was a fault. I suggest you perform the Briggs-specified output current test:

System 3
, 4
and Dual Circuit Alternators
Alternator Output Test Procedures
Test DC Amp Output
1. Insert RED test lead (3) into 10 A receptacle in
meter.
2. Insert BLACK test lead (2) into COM receptacle in
meter.
3. Rotate selector to (DC amps) position.
4. Attach RED test clip to stator output lead (4),
Fig. 16 (Typical).
See Fig. 17 for Dual Circuit alternator. The RED
wire (5) is DC output. The bump on the connector
indicates the DC output terminal (6)
5. Attach BLACK test clip (2) to the positive (+)
battery terminal or charging harness lead (1).
6. With engine running at specified RPM, output
should be as listed in Table No. 2, Specifications.
7. If low or no output, check stator air gap, when
applicable. See Table No. 2, Specifications.
8. If stator air gap is within specification and there is
low or no output, replace stator.


Extract from Table No. 2 for your system (System 3 & 4):
DC Only Alternator and Dual Circuit Alternator
Output: Between 2 to 4 amps DC @3600 RPM.
Output will vary with battery voltage. At maximum
battery voltage, output should be approximately 2
amps.

If you do not get the specified current, we can talk about what to do next, which will be clean various terminals and set the alternator air gap.

Getting 2.3v dc

Do you mean 2.3 Amps DC? If you do, that is within specification for your system.

Oops yes 2.3 amps. Looks like all is good

Thanks for your help

It's been a pleasure. We don't have nearly enough Cox ride-on cases in our archive, and with your mower being in such authentic and original condition, it has been neat and tidy to deal with.

I'll close this thread. If anyone needs to post to it, just send a PM to a moderator.