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Discussion Starter #1
I bought a Gravely 16G. It has an Onan 16.5 HP CCKa-MS. It runs well and makes good power. The charging system isn’t working. The stator is producing 26 volt AC at the leads. The original 4 wire rectifier/regulator from Onan is no longer available. I have put on a 3 wire 15 amp Kohler regulator and moved it off of the engine and under the hood. The regulator is only producing 6 or 7 volts DC. All the wiring is new and making a clean connection. I’m not sure what to look at next. The stator output is good according to the Onan manual I downloaded. I swapped out the rectifier but got the same result on the DC output. I feel like it must be the stator but the manual said above 17 volts was good. I have continuity between the two stator leads. I do not have continuity between the stator lead and the metal body of the stator. Any of you gear heads have a suggestion?

thanks
Jon
 

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Kish JD 318/420/430
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VR is below the manufacturer recommended voltage output most likely it not a full wave rectifier versus a half wave rectifies. You could make your own from 4 very large diodes and a zener diode (13.8 VDC) with current handling capability.
 

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I bought a Chinese clone of the Onan reg/rectifier for under $20 on eBay. Here is the link, Regulator
Sorry if I was not supposed to post this. But it is 3 wires. Outer two from the stator, and the center is B+

Oh, and this is for my Onan p220
 

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Discussion Starter #4
VR is below the manufacturer recommended voltage output most likely it not a full wave rectifier versus a half wave rectifies. You could make your own from 4 very large diodes and a zener diode (13.8 VDC) with current handling capability.
Thanks so much for the input. I will look into that. Can you educate me a little? The rectifier that I am using is a Prime Line 7-01697 I bought at NAPA. It doesn’t have much literature with it and doesn’t say anything about full wave or half wave. I had thought that most any regulator would work. The original regulator isn’t available anymore. What would be a good replacement?
Jon
 

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Kish JD 318/420/430
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I found this: Onan voltage regulator/rectifier - Yesterday's Tractors
Looks like two wires fed DC output to two different things, with two wires for AC input from stator. Read the complete thread and post what you did so I know we are on the same page with engine and tractor. Did you modify the wiring (eliminate the 4th wire to the coil)? Hopefully just taped it off. The B+ wire should go to poitive of battery though a 20 amp fuse and wire to handle 20 amps ( 12 gauge wire). Power to coil needs to from battery to key switch to coil positive (+) terminal, with points and condensor on the negative (-) terminal and ground. Unless it is an electronic ignition. It is possible that the VR is bad from the start (electronic parts have a none refundable clause usually). I'm wondering about your mounting location (where is under hood). I would use firewall or tractor frame (proper grounding and heat sink capability.
 

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Discussion Starter #6
My first thought was that the new regulator was bad. I bought a second one from Napa ( Prime Line 7-01697) but had the exact same results. Both regulators gave between 6 and 7 volts DC when the engine was running at full throttle. The new mounting location is behind the dash near the hobbs meter and some sort of timing circuit. I was also concerned about the new VR not having a good ground so I triple checked that and even went so far as to run a jumper from the body of the regulator to the negative on the battery just to be able to completely eliminate that possibility. I changed the location of the original regulator from the engine block using 12 gauge wire. I soldered and shrink wrapped the connection between the new wiring and the stator rather than attempt to reuse the old 4 plug connector. The old connector itself is interesting as it had 4 wires but one apparently did nothing. There were 2 wires that went from the stator to the VR. There were 3 wires coming from the VR. In the actual plug that connected the stator to the VR there were 4 wires. The 4th wire went to the positive plug on the coil. I cant see that this wire did anything as it actually terminated in the plug connecting the VR to the stator without actually making a connection with anything. I can put my meter on the two leads going from the new location behind the dash to the stator and get continuity. I can check for continuity on one of the stator leads and the metal body of the stator and there is not continuity. When the engine is running I get about 26 or 27 volts AC between these two leads. The manual I downloaded stated that above 17 volts AC was good however I noticed in the link you found and sent to me RSteveH noted that he was getting 52VAC from the stator. That makes me wonder if my manual is correct. Same engine but if he is seeing 52VAC is the 26VAC I'm seeing suffecient. What have others gotten from their stator output for similar Onan engines?

Thanks
JON
  1. I found this: Onan voltage regulator/rectifier - Yesterday's Tractors
    Looks like two wires fed DC output to two different things, with two wires for AC input from stator. Read the complete thread and post what you did so I know we are on the same page with engine and tractor. Did you modify the wiring (eliminate the 4th wire to the coil)? Hopefully just taped it off. The B+ wire should go to poitive of battery though a 20 amp fuse and wire to handle 20 amps ( 12 gauge wire). Power to coil needs to from battery to key switch to coil positive (+) terminal, with points and condensor on the negative (-) terminal and ground. Unless it is an electronic ignition. It is possible that the VR is bad from the start (electronic parts have a none refundable clause usually). I'm wondering about your mounting location (where is under hood). I would use firewall or tractor frame (proper grounding and heat sink capability.
    [/QUOTE
 

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Discussion Starter #7
Ordered and installed a full wave regulator. Realized the first one I installed was a half wave. Problem solved. Thanks to Rushkish.
 
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