310-8 charging issues... Stumped!!

[bwcollins 1]

Hey guys, I lurk a lot but don't post much.... here is the back story of my issue,

    I have a 1990 310-8 with the Kohler M10 in it. The tractor has plowed snow and ran fine all winter no issues. (With the exception of an old battery and I had to jump start it for a while until i pulled my other horses battery for it I pulled the battery to use in my b80 for mowing duty, however the head gasket gave out so i put the deck on my 310 and switched the battery back over. At that point the tractor wouldn't start, but jumping the solenoid it would run fine and I mowed my 1 acre a few times.
     Then I noticed the headlights weren't working either at this point but just figured it was the solenoid. I replaced the solenoid with the same issue, and started checking fuses. The 5 amp headlight circuit fuse was blown. I replaced the fuse, tractor fired up, bumped the throttle and fuse blows. Same thing with a 10 amp and 15 amp. Meanwhile the 15 amp starter circuit is fine. The fuse does not blow at idle, just when the throttle is upped at all, the bigger the fuse the higher up i can go. 20 is the highest I tried. Figuring I had a small short, I retraced the entire harness with no luck.
     My tractor also has the clutch safety and seat switches bypassed so no issues there. The amp meter and hours work, until the throttle is upped and the fuse blows and I lose that circuit. I do not have a multi meter, but used my battery charger to check the alternator output and battery power (it has a setting just to check alternator and battery volts with engine running). Sure enough, when the fuse blows, the stator quits charging and returns to battery power. With a 5, 10, or 20 amp fuse, it will charge until the throttle is upped enough for the fuse to pop and then stops charging. The only part of the wiring I am unable to check is the small section behind the flywheel. My mind is telling me the small voltage regulator on the flywheel cover is bad. When that is un-plugged, the tractor runs fine and everything works as should. I believe that is only battery power though....

Any suggestions? Thoughts? I am stumped and my yard is getting a bit high haha

[Save Old Iron 1,573]

Troubleshooting this issue without a multimeter can be done, but most of what we discuss will be guess work.

I'm not convinced there are any issues at all with the stator or wiring behind the flywheel. The fact the stator can produce enough amperage to blow a 20 amp fuse indicates the stator is in very good health.

Using what we have, do you see the amp meter indicating a large current flow when the RPM's are increased?

Without a multimeter, the only other non guessing  troubleshooting would have you visually checking all wiring for abraded insulation and shorts to chassis ground.

Yes, the voltage regulator could be bad, but the bigger question is where is 20 amps of current going?

 

Edited May 24, 2015 by Save Old Iron

[bwcollins 1]

The amp meter seems to work, but doesn't change a whole lot when rpms are increased and appears to work normal. I am going to buy a meter today, could you give me some ways to try and troubleshoot what I have? Other than the basics, I am not sure where to start with a meter, thanks in advance

[Save Old Iron 1,573]

My mistake. Your 310 should have a voltmeter, not an amp meter

When you grab a multimeter, let us know what brand and model you purchased so we can orient you to its correct usage.

If your grass is getting high, you should be able to run the tractor without the charge system hooked up.

[bwcollins 1]

http://www.amazon.com/Craftsman-34-82141-Digital-Multimeter-Functions/dp/B000X5TSUA

That is the model meter I bought today.... What should be my first step in trying to troubleshoot THIS problem. It has been a long time since I have had to use a meter for this in depth of wiring troubleshooting so bear with me if i sound like an idiot at times! Thanks

[Save Old Iron 1,573]

Initial thoughts

Make sure the new battery placed in the tractor is connected properly, + terminal on battery to + battery cable, etc. Double check.

 I'm going to ASSume all the fuses have been replaced with proper amperage replacements. Let me know if this not the case.

 Select the 20 Volt DC setting on the multimeter,



red meter lead connected to the battery (+) and the black meter lead to the battery (-) terminal.

Record the battery voltage with the engine off. The battery voltage should be in the 12.6 volt range. Post the result to the forum.

Start the engine and keep the engine at idle speed.
Record the DC voltage on the battery terminals. Normally, this voltage will be 13 - 15 volts. Post the result to the forum.

Increase the engine speed while monitoring the battery voltage.
If the battery voltage goes above 16 volts,



back the engine down to idle.

If the battery volts go above 16, we will begin to troubleshoot the Rectifier / Regulator 
 

Edited May 26, 2015 by Save Old Iron

[bwcollins 1]

 thanks for the guidance!

    I forgot to mention there are a few butt connectors in my wiring system but they are in good condition and appear to be the same wires. I got the tractor for 200 bucks and it ran, and I never messed with it. I never looked at what fuse was in the system but wheel horse states a 5 for the 1990 310-8. I tested battery before running engine and it was 12.58.... checked at idle it was 13.15... increased idle and it immediately popped the standard 5 fuse above idle. However, I placed a 20 in and the volts never went above 14.14. Volt meter works as should just like the hour meter. 

     Just for kickers, I put a 25 in, and I could not get the fuse to pop. It never ran above 14.15 volts either. Ran it full throttle, and deck, mowed, and tried to get it to pop and it won't. Lights also work no problem. Am i crazy to think to just run it this way? The engine is obviously charging correctly based on voltage, and the battery is good. The regulator seems to be working because I never got over 14.15 at the battery at any time. Is it Possible the wiring harness was adapted for something and still works correctly so it doesn't need changed?? I haven't completely patterned it like a 1990 harness diagram but nothing looks out of the ordinary based on my standard knowledge. I based the fuse blowing on the standard 5/15 system that should be in the 1990 310-8.  So it was puzzling when the 5 fuse kept blowing...

Opinions?? Recomendations?? I want this thing to not be a fire hazard but the fuses don't get hot, and everything runs fine!

[pfrederi 19,256]

They used two different charging systems on 310-8s  One had a fixed 3 amp unregulated charging system...no regulator that would seem to match the spec for the 5 amp fuse.  All of the later models with real regulators I believe used 15 amp systems so yeah it would blow a 5 amp fuse when it was charging hard.  The otehr 15 amp systems I have seen do use a 25 amp fuse.

[Save Old Iron 1,573]

+1 on what pfrederi said.

If you are using 2 PAR headlights, that current draw alone would be 6 - 7 amps. Circuits are usually fused for for 1.5x normal draw, so the headlight fuse should be at least 10 amps. The wring diagram shows a 15 amp fuse for the headlight circuit.

Edited May 25, 2015 by Save Old Iron

[Save Old Iron 1,573]

Add a possible 15 amp battery charge current to a 7 amp headlight current and a 25 amp main fuse makes sense.

The wiring diagram for your model shows a 25 amp main fuse.

Having said this, there should be no reason for a 20 amp main fuse to be blowing and a 25 amp fuse holding. Once the battery recovers the charge used during cranking the engine, charge current should taper off to under 2amps.  Throw in another 7 amps headlight draw and you still have less than 10 amps thru the main fuse.

Suggestion? 

I believe the 5 amp fuse issue has been addressed - insert a 15 amp fuse in its place.

I can outline how to do a voltage drop test across the main fuse holder. Fuses blow basically by melting the inner element. If the fuse holder is corroded, and self heats under moderate current draw, the fuse has a "head start" toward premature trpping.

I'll post more later tonight.

Edited May 25, 2015 by Save Old Iron

[bwcollins 1]

So basically first off, I had the wrong fuse size/diagram for the 1990 310-8? That makes more sense to me and solves why a 5 or 10 would blow almost immediately. The 15 will also blow but that happens at 3/4 throttle. So basically I probably have a corrosion issue in the fuse holder? My starter circuit has a 15 in it and there is no issues there. Is this the correct fuse for that size? Thanks again gents!

[boovuc 1,090]

I thought, (note the word "thought"), that all the Kohler Magnum 10 horse tractors were the in-wire diode, 3 amp charging systems. The 310-8 speeds with the K series used a "real" charging system of 15 amp. 
I have two 310-8 speeds. One is a Magnum and the other has a K series in it. The charging/electrical systems between the two are day and night apart!

[bwcollins 1]

Mine 1990 310-8 has the m10 Kohler by the way if this helps, and Save old iron is there anyway to find this diagram you are referencing? I didn't see it in the library 

Edited May 26, 2015 by bwcollins
Add sentence

[Save Old Iron 1,573]

this makes the mystery even greater - the Magnum engine does not require ANY power from the battery to run, only to start.

Once the Magnum is started, it will run without any further battery power.

If all that requires power from the stator is brief battery recharge after start up and possibly headlights / taillights when and if you have them on, how could this possibly blow a 20 amp main fuse?. If headlights / tail lights are off,  less than 1/4 amp in used in the voltmeter and hour meter circuits. Safety circuit relays maybe another 1/2 amp max.The indicator pcb maybe another 1/4 amp.

You keep mentioning 3 fuses. Can you confirm your system had 3 separate fuses?

The headlight fuse should be 15 amps according to the schematic.  This one we can put to rest.







You mention a starter fuse. The schematic does not show any fuse in the start circuitry. The 25 amp fuse seen below is the "main" fuse off the battery charge circuit.










The "main" 25 amp fuse is in the battery circuit.




The next step is to identify (maybe by a picture) where your "starter" fuse is connected.
You may also want to advise us on where the crimped connectors are in the circuit. This may be valuable as we move forward in troubleshooting.

Suggestions??
Inspect the wiring harness that flows near the steering wheel shaft. Yours would not be the first fuse blowing intermittent short from bare wire caused by constant rubbing against the steering shaft. This could explain the 20 amp fuse blowing but not why a 25 amp would not.

Edited May 26, 2015 by Save Old Iron

[pfrederi 19,256]

My 310-8 has a K series Kohler and the 3 amp unregulated system.  The headlights run on AC off the stator. Appears to be original....

[boovuc 1,090]

Well that blows that thought process all to hey!
I see in 1986 there were two model numbers of 310's with the K series. (21-10K802 & 21-10K803). Quite possible this is one of or the only difference between the two models? I can't tell what my K-series 310 model number was. I surmised it was a 1986 by the build number on the motor. The ID tag was completely bleached out with no numbers visible. I even sprayed a little blue dye on it hoping it would pick up the trace of what was there but it didn't work. Thanks for posting that, Paul. It's good to know going forward and I apologize for the slight hijack. 

[pfrederi 19,256]

Well that blows that thought process all to hey!
I see in 1986 there were two model numbers of 310's with the K series. (21-10K802 & 21-10K803). Quite possible this is one of or the only difference between the two models? I can't tell what my K-series 310 model number was. I surmised it was a 1986 by the build number on the motor. The ID tag was completely bleached out with no numbers visible. I even sprayed a little blue dye on it hoping it would pick up the trace of what was there but it didn't work. Thanks for posting that, Paul. It's good to know going forward and I apologize for the slight hijack. 

​Model is 2110K801  serial 13167

[gwest_ca-(File Mod) 11,844]

Not all 1986 models have 2 model numbers but most do.
Have long suspected the only differences is the first was produced by Wheel Horse and the second by Toro.

Garry

[Save Old Iron 1,573]

We still have the unanswered question why a 20 amps fuse blew on throttle up but a 25 amp did not. Most multimeters cannot read 20+ amps of current directly. Your meter is only good to 10 amps.

If you have access to about 4+ feet of 14 AWG solid wire - like used in home repair - we can build a current shunt to directly measure how much amperage is actually flowing thru the 25 amp fuse now in place.

Let me know if you can obtain the 14 AWG SOLID wire. After we make a current measurement, we can either continue to troubleshoot or put all our original questions to rest.

Edited May 29, 2015 by Save Old Iron

[bwcollins 1]

I will let you know, I have been real busy with work and haven't had a chance to mess with it again, I'll keep you guys posted.... And yes it is a 1990 based on the serial number Sent from my iPhone using Tapatalk