John Deere 318 with Starter noises and Blowing Regulators Rectifiers

[Jack in Michigan]

My John Deere 318 with P218 Onan engine is blowing regulator rectifiers and I can’t figure out why. It just started this last Friday; I was having starter noises, so I purchased a new starter (I did install a starter improvement kit) . Before replacing the starter, the battery light would always come on until the engine ran for a short period; then it would go off. After we pulled the engine and put the new starter in the noise was even worse than the old starter was. My buddy thinks it is the ring gear, he is probably right, but I am a little skeptical (it is almost like the starter should have some shims or something). After the starter was replaced and the engine back in, the battery light would not go out. Did some checks and the regulator rectifier was bad. I found another one and what I thought was a fix was not. The light went out and it seemed to work ok for about 5 to 10 minutes and then that one went out too. If you gents out there have any suggestions on what to do with my issues please post a response. Thank you in advance for any post. Jack in Michigan

 

[wore out]

My John Deere 318 with P218 Onan engine is blowing regulator rectifiers and I can’t figure out why. It just started this last Friday; I was having starter noises, so I purchased a new starter (I did install a starter improvement kit) . Before replacing the starter, the battery light would always come on until the engine ran for a short period; then it would go off. After we pulled the engine and put the new starter in the noise was even worse than the old starter was. My buddy thinks it is the ring gear, he is probably right, but I am a little skeptical (it is almost like the starter should have some shims or something). After the starter was replaced and the engine back in, the battery light would not go out. Did some checks and the regulator rectifier was bad. I found another one and what I thought was a fix was not. The light went out and it seemed to work ok for about 5 to 10 minutes and then that one went out too. If you gents out there have any suggestions on what to do with my issues please post a response. Thank you in advance for any post. Jack in Michigan

I don't know what to say about the starter noise, and I don't know you are determining it is "blowing"
rectifiers, the only thing I can contribute is that there were known grounding issues between the battery and the chassis and the engine.

 

[Jack in Michigan]

Hello wore out, I was hoping that you would have some input, as well as others. The regulator / rectifier burnt out just after we put the motor back in and started it up. As I stated before it was working properly, then I put another one in, it worked for a minute and blew. I am going to attach a video, you may not be able to see it, but I hope you all can here the sound that it is making. Thanks

 

[wore out]

Hello wore out, I was hoping that you would have some input, as well as others. The regulator / rectifier burnt out just after we put the motor back in and started it up. As I stated before it was working properly, then I put another one in, it worked for a minute and blew. I am going to attach a video, you may not be able to see it, but I hope you all can here the sound that it is making. Thanks
View attachment 86110

I'm not figuring out anything from your sound recording, but could there be a loose part banging around in the air shroud, or perhaps the flywheel is loose or the stator wires got entangled in the flywheel or perhaps one or more magnets have come unglued from the flywheel?

I'm afraid you are going to have to pull the engine and air shroud and have a look!

 

[Jack in Michigan]

I will pull the engine out this week, Thank you wore out!

 

[T.R.K.]

I have a 318. I was given the tractor because the ring gear was bad. That was over 15 years ago. Deere only wanted to sell a flywheel with the ring gear on it. (at Insane $) At that time Cummins Atlantic was still handling Onan parts and they sold me just a ring gear. I had to heat and mount it just like you would do on a car. I don't use that 318 much any more but it always started well after I put the ring gear on it. It does have the starting improvement kit on it.
You need to inspect the ring gear for worn or broken teeth when you remove the engine.

For you regulator problem, with the engine running, use a volt meter to check the two wires coming from the stator. I don't know Onan specs but most everyone else (except for some old Kawasaki engines want to see about 30 volts AC from the stator under the flywheel.
Another test with a volt meter is to check across the battery posts. If it is over 13v. there, the regulator is charging the battery (or trying to charge it) and that light is just lying to you. Probably because of a bad connection somewhere.

 

[wore out]

I have a 318. I was given the tractor because the ring gear was bad. That was over 15 years ago. Deere only wanted to sell a flywheel with the ring gear on it. (at Insane $) At that time Cummins Atlantic was still handling Onan parts and they sold me just a ring gear. I had to heat and mount it just like you would do on a car. I don't use that 318 much any more but it always started well after I put the ring gear on it. It does have the starting improvement kit on it.
You need to inspect the ring gear for worn or broken teeth when you remove the engine.

For you regulator problem, with the engine running, use a volt meter to check the two wires coming from the stator. I don't know Onan specs but most everyone else (except for some old Kawasaki engines want to see about 30 volts AC from the stator under the flywheel.
Another test with a volt meter is to check across the battery posts. If it is over 13v. there, the regulator is charging the battery (or trying to charge it) and that light is just lying to you. Probably because of a bad connection somewhere.

Also need to check the stator for shorts to ground.

 

[Jack in Michigan]

Hello everyone, This is where I currently stand. I did all of my electrical checks, the stator seems to check fine, the resistance is low and there is no direct short to ground, before I pulled the engine out I was getting over 30 volts ac from the stator, and when I put the leads across the battery posts, I was only getting about 12.4 volts, so I know it is not charging. I have about the same, 12.4 volts at the battery lead that plugs into the b + spade on the regulator/rectifier. My engine is all disconnected and ready to pull out and hope to get back on it by this weekend. I will check all of the suggestions I received once the engine is out. I ordered a new regulator/rectifier and should be here by the time I put the engine back in. Thanks for all of your suggestions, Jack

 

[kencombs]

When you do the electrical work, be sure the regulator is grounded. Also, most mowers/small tractors run the charge current through the ignition switch, so a bad plug connection on it can cause a no charge condition.

 

[BradCNY]

There is usually a fuse or circuit breaker between the rectifier and the battery to protect the rectifier. Trace usually the red wire from the rectifier to see were it goes.