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318 Dies When PTO or Hydrostatic Control Lever Engaged

4K views 13 replies 6 participants last post by  sask112 
#1 ·
This is a 1986 318 with the B43G Onan, serial # 362641. When the PTO or Control lever are moved the engine dies. I have checked seat switch, charging system and fuses. The PTO light does not come on when key is in the run position. I have been looking for a wiring diagram but have not had any luck. Any ideas or a link to a wiring diagram? Bob
 
#2 ·
Robert,

Welcome to the WFM forum!

The wiring diagrams are in the technical manual for your tractor, TM1590, which is very highly recommended that you purchase for ongoing maintenance. I can send you an excerpt by e-mail of just the schematic as even it is too large to post here.

Is this a new to you tractor? Any idea if the wiring was cobbled by a prior owner? Here is a partial diagram showing the wiring around the ignition and safety switches. If the PTO is off, the seat switch does not have an effect normally.


Chuck
 
#3 ·
Chuck,

Thank you for your response and the schematics that you sent. This tractor is new to me, previous tractor was a JD 317. The original problems with tractor were (1)oil leaking, (2)Battery Light on. Oil leak was oil filter housing gasket, removed housing, cleaned, RTV on gasket and Liquid Teflon on bolts, leak stopped, ordered new gasket. Charging system check shows regulator to be faulty, substituted a 15amp regulator from 317 and battery light went out and Volt Meter shows charging, ordered 20amp regulator.

With above partial repairs done I drove tractor across the yard and engaged mowing deck, deck and tractor ran for about 10 seconds and died. Shut deck off, started tractor and went to move forward and tractor died. The only way to move tractor was to jump neutral safety. I did jump the seat switch but that did not help.

I will get to work using your schematics and report back.

Thanks, Bob
 
#4 ·
Chuck,

Thank you, after troubleshooting with the schematics you sent I found two problems. The first problem was with the 20A fuse holder, the fuse was good and there was voltage on both sides of the fuse holder, but only sometimes. The terminals on the wires inside the fuse holder had corrosion on them, replaced the fuse holder and that problem was fixed.

The second problem involved the seat switch. I know I stated I checked it and I did but after further troubleshooting I found that someone had added a 4" extension to the harness. The factory plug was under the rear body and the extension came out of the body to the seat. When I jumped the harness yesterday it had no effect because one of the connectors on the extension was bad.
I had to make a temporary jumper as I am ordering a new seat and switch this week.

I would say the wiring was cobbled by the previous owner or dealer.

While I was involved in the wiring issue I did take the time to clean all the wiring connectors in the battery box area trying to avoid further issues.

Thanks again, Bob
 
#7 ·
I'm not positive it's the starter. But in going through the "troubleshooting" section of my owners manual, regarding the non-starting of the tractor, the starter is whats left. Safety switches are good (as far as I can tell), fuses are good. Battery is good, grounds are all connected (battery, starter), there is no shortage of output from the battery, so all I can think of that's left is the starter. Unfortunately, it's a holiday here and the starter reman places are closed. The local partsource can't find my starter in their system to test it, and the JD dealer closed 2 minutes before I got there today. Found a starter off of a parted out unit for a fraction of the cost. Can't find anything aftermarket on e-bay, which surprises me!
 
#8 ·
Scott, I don't know what you've all checked, but you need to measure voltage at the starter. A starter will typically have 3 connections, 2 being heavy wires, and one small signal (solenoid) wire. One large wire should have 12 volts all the time, the small solenoid wire should have 12 V when you try to start, and the other large wire should get 12 V when the small one has power.
 
#9 ·
Scott, some diagnostic work is needed here. Do you have 12 volts at the small solenoid terminal when trying to start? I assume this starter has a Faston tab connector for the solenoid, similar to the smaller Yanmars in 330/332. The terminal has to be clean, and the harness connector has to make positive contact.

If you have the starter off, you can bench check it. Clamp it in a vise, so it can't jump around.
Connect +12 volts to the battery cable connector, and ground to the starter frame, using jumper cables from a charged battery. Jump across from the battery cable connector to the solenoid terminal. Normal operation is for the solenoid to shift the starter pinion, and make the starter motor spin. If you get no solenoid action, shift the ground to the other big terminal on the solenoid (the one connected to the starter motor) and jump from +12 to the solenoid terminal.

If the solenoid pulls in, the starter motor is open circuit internally. Most commonly worn brushes or a bad ground connection inside. Both repairable.

If the solenoid does not pull in, the solenoid is defective (open pull-in coil).

It's very rare that a sick starter motor can't be brought back to life with a simple brush and bushing replacement. A good auto electric shop should be able to do this for you.

I don't advise "aftermarket." What's being offered as aftermarket for Kohlers and Onans is cheap Chinese junk, and being sold non-returnable.

Hank
 
#10 ·
I'm not as electrically proficient as I should be, thus I removed the starter and took it to a reman shop, for testing (in the least). In the meantime, I do recall the positive connection shaking loose at one point (not enough to come completely unplugged), but being sloppy. I am thinking about replacing the positive connector from the battery.
 
#11 ·
Scott, plan on getting a bit of electrical proficiency. Chuck Van Dusen and I are both electrical engineers who can give you some guidance, and most tractor electricals are pretty simple, both in concept and in execution.

Chuck may disagree to some extent, but my feeling is that at least half the electrical problems on these tractors are connector and other wiring problems, not component failures. It's important to diagnose first, then repair.

Most troubleshooting is done with a multimeter, a VOM (volts-ohms-milliamperes) meter. I much prefer an analog meter (with a meter movement) to a DVM (digital volt meter) for trouble-shooting because how the needle moves---smooth vs. erratic---is a major diagnostic indicator. A DVM just gives you spinning numbers. You can get a cheap analog VOM at Radio Shack for, I think $25.
Also, there are test lights that look like screwdrivers or ice picks with a bulb in the handle and a wire lead used to complete the test circuit.

I mentioned a "Faston tab" on your starter. Faston is the manufacturer's trade name for the flat tab (male) tabs that connect with curled-edge female connectors, with a hole in the tab and a click-in dimple in the female body. Manufacturer is TE (formerly Tyco). If those get corrosion inside, they'll make poor connection, and if loose, they go intermittent. The chemical I use for corrosion is Caig Deoxit D-5. There is a new article in the FAQ section on that subject. If loose, you can squeeze the curly ears some to tighten them back up.

"Loose and corroded" was what was giving me intermittent starter operation on my 330. "Diagnosis" was reaching in and wiggling the connector while trying to run the starter.
"Fix" was Deoxit and a judicious squeeze with duck-bill pliers (yes, through the rubber) to bend the ears "enough." Cost of diagnosis and repair, pennies (for the Deoxit).

Hank
 
#12 ·
Hank,

I agree that a majority of initial failures on these machines are connection related, due to age, weather exposure, vibration and in a few cases lost spring force due to overheating from excessive currents. As our vintage garden tractors age, there are also some component failures that show up in the mix of root causes.

Unlikely the case for Scott's 2004 2210, but a good portion of the woes found in previously owned machinery are induced by a prior owner hacking the wiring in an ill advised attempt to bypass some safety function or some other 'shade tree' modification when they are not guided by the factory manuals and the generous help of the fine folks on these forums.

Scott, best of luck on the starter...most likely it will not turn out that an expensive replacement needed, but just proper connection maintenance like Hank mentioned.

Chuck
 
#13 ·
Turns out the starter is fine. The reman place I took it to commented on some pitting internally, near where the positive connector is. I think that connection is loose, to the point it's not making contact. I don't think I can squeeze it, the outer casing is hard plastic. I'm going to try and tighten it up a bit, but I think I'll end up replacing the female end. Also,my positive battery post is dirty, and the clamp on that side (cheap cast) has cracked. I'll be replacing that as well. All in all,I'm happy I don't need to spend big $$$ on a new starter.
I know what I'll be doing tomorrow.....
Thanks guys for the help. I'm embarrassed to mention that my Uncle is a retired electrical engineer, I obviously didn't pick up my electrical smarts from him!!!
 
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