[Hammerdown-7]

Hello Guy's
I Picked up an Older 318 this spring and it has run great so far, but I have a problem starting to develop with it. Sometimes after I start it up, it keeps the battery light on in the dash until I rev it up a bit, and then it goes out. Yesterday I mowed with it, and realized it was NOT going out no matter how High I revved it up, with the deck engaged. I then saw where I apparently left the Headlights on from the last late mow I did with it, so shut them off and the Battery Light in the dash went out. Can you share with me what might be going on with it ? Thanks in advance to all that replay. Regards, Kurt

 

[chuckv]

Kurt,

The battery charging light on the 318 is an indicator of battery voltage condition, not of current flow -- here is a quote from teh theory of operation section in the TM1590 manual:
<font size="-2"]Battery discharge lamp control (A) senses battery
voltage present at fuse (F2). If the lamp control
senses low voltage (less than 12.3 volts), it will
provide a path to ground for battery discharge lamp
(P4). Since battery voltage is always available at the
discharge lamp when the key switch is in the RUN or
START position, the ground path provided by the
lamp control will allow battery current from fuse (F1)
to flow through the battery discharge lamp to ground,
lighting the discharge lamp. The lamp will stay on
until battery voltage increases to 12.7 volts. At this
point, the battery discharge lamp control will break
the path to ground, turning the battery discharge lamp
off. [/COLOR]


Note that the voltage needs to get above 12.7 volts (as sensed by the TDCM module) for the lamp to go out. Since you had a lot of loads on the battery with the PTO and the lights on it may have taken a while for the battery to get fully recharged from having started the tractor. If you have an older battery at the end of its service life, or it is low on water in the cells, then it would not take a charge very well either, compounding the issue.

It is of course possible that the voltage regulator is beginning to fail, but try the easier things first like having your battery checked at your local auto parts store. If you have a digital voltmeter, you can measure the voltage at the battery and confirm if the charging circuitry in the tractor is working correctly. There is a detailed test procedure in the TM1590.

Below is the partial wiring diagram for the charging system in your tractor...

Chuck

 

[Hammerdown-7]

Hello Chuck
Thanks for the detailed information on this current issue I am having here. I strongly suspect that the Voltage Regulator is on it's way out,as the battery is fine and of 750 CCA. I Know John Deere would Lay me Wide Open for a new Voltage Regulator, do you know of an Out side source for these that would work on my Onan engine ? Thanks, Kurt

 

[whstubb]

Check Ebay there is one on there brand new for $34.00 plus shipping, I bought one from there about 2 years ago, still working fine.

 

[chuckv]

Kurt,

The NAPA stores also have replacement regulators -- their part number is 7-01699 and should be quite a bit less than the same part from Deere.

You should also be aware that a Cummins/Onan dealer has all the parts for the Onan and will be less than the Deere pricing as well. I have found that they also seem to have most parts in stock where Deere needs to special order them in most cases. Just drop the "HE" prefix on any Onan-related part listed in the PC1924 to arrive at the Cummins/Onan part number. The number for the regulator for instance is 191-2106. A further advantage for me is that Cummins parts department here in Portland, Oregon is open till midnight.

Chuck

 

[Hammerdown-7]

Hello Chuck
Thank's for the Napa Part number.. I have a friend that is a Manager of a Napa store near me... Regards, Kurt

 

[Mike_johanson]

Take a look at plug on back of ignition key, move it around.
Bet its a bit rusted and causing your issue.
was with mine and Andrew's.

Mike

 

[Hammerdown-7]

Hello Mike
Thanks, I will Look at that as well... Regards, Kurt

 

[extmc]

Had same problem with my 318. Today bought new battery, new rectifier from Onan, and installed both. Removed old battery first, replaced rectifier as per instructions, then replaced new battery. Resistance from B+ on rectifier to B+ on battery is 0. Engine will not turn over. Battery lite on dash on. Can hear what appears to be solenoid on starter click. Battery voltage is 12.7. Any ideas? New poster, long time reader of this forum. Thank you, Chris

 

[chuckv]

Chris,

Welcome to the WFM forum!!

The regulator does not need to be connected for the engine to crank and start. Look at the wiring diagram below -- the power for the solenoid must go through two sets of contacts within the key switch, so start by replacing that switch (they wear out in 20+ years of use...)

You also want to verify that the 20 amp fuse is good and that the fuse holder is making good connections. Older 318 tractors with the glass cartridge style fuses have been known to have less reliable contacts in the fuse holders, so upgrading to the later tab type automotive holder and fuse is probably a good idea.

Lastly you can see from the diagram that all the safety switches must be in the proper state to allow starting. Early tractors do not have the brake switch, but the PTO must be off and the hydro lever in the neutral slot. You may have to hold the lever firmly bottomed in the slot (toward the steering column) if the neutral switch is starting to get out of adjustment.

Let us know what you find and we can continue helping you troubleshoot if needed. Good luck!

Chuck

 

[mello_collins]

Kurt,

I had the exact same symptoms as you and it was the regulator. The napa replacement is made in USA, not china.

 

[extmc]

Thank you Chuck, Today I went back to look what I had done last night and retraced my steps. I had used the compressor and air hose to blow everything off before starting to replace anything. Stupid me caught the wire from the starter relay and must have pulled it off. I didn't look at the starter until today. One note, on the replacement of the regulator, I purchased an Onan form the dealer, and it was slightly larger than the original. Dremel worked great at enlarging the opening. Put wire back on starter, engine fired right up. Tractor hasen't run this good in a long time. I also re gauged the front clutch. What a difference. Thanks to this forum that job was made easy.
Thank you for your help. Chris

 

[howard hudson]

been searching for an answer for my problem and cant find it. So I will just ask it on this thread. Is the red and white wire that connects to the rectifier B+ term have currant with the ign switch on and off or just on ?

 

[chuckv]

Howard,

The white with red stripe wire from the center terminal (X13) of the voltage regulator on the Onan engine only puts out current when the engine is running. Because it connects directly to the battery through the circuit breaker as shown in the diagram below, you will always measure a voltage on this terminal even with the key off, but current is not flowing...

Chuck

 

[howard hudson]

Thanks Chuck

 

[Carndog64]

As a note Chuck just helped me with a similar issue. I replaced my regulator and the battery light stayed on. I reconnected the wires just like the old reg. What the new one has is the center terminal is connected to the outer thats where I got confused. The striped wired always goes in the center and stator wires ( both black on either outside terminal. As a note any of the engine parts are available thru Onan/cummings alot cheaper than JD. My new reg was 54 dollars.

 

[khe]

Kurt,

You might also check the resistance of the PTO clutch coil. I had symptoms like you describe and my stator was fine, the regulator output was fine, the battery load tested OK. The PTO coil was 0.8 ohms when it heated up. I replaced the coil and it was fine.