Onan P220 for my 520H

[RT WH416H 10]

Need help...I have a 520H and I have not worked on small engines other than basic maint.

My P220 is showing that it is not charging the battery. I got a new battery and after using it a bit, it will not start. I know the basics of looking for wires shorting and other basic.

I have the manual also. Should I start with the rectifier regulator. It is cheap enough.

Any thoughts and suggestions appreciated!!!

[stevebo-(Moderator) 8,364]

Change your voltage regulator on top of the motor. 

http://www.ebay.com/itm/New-Voltage-Regulator-Rectifier-For-Onan-16-18-20-22-24-HP-Engines-/331722291511?hash=item4d3c307937:g:4TgAAOSwf-VWXeY5&vxp=mtr

[Ed Kennell 39,288]

Pull and check the legs of the fuses.   Don't forget the one at the front of the tractor near the starter.     And, yes the RRs are suspect and relatively cheap, but I would pull the fuses and every connector 3 times to clean the lugs. And loosen and clean all the ground connections  including the bolt that fastens the RR to the tin.  These 520 wiring  connectors have a tendency to corrode and loose contact.

You may find your RR is OK, but it is a good idea to have one in stock, as it will fail eventually. 

 

Good luck....keep us posted,    and   to the

 

[wallfish 17,128]

Test it for DC voltage out with a multi-meter first.

You can also test the wires coming from the engine too if there's no voltage coming out, 2 wires go to the rectifier/regulator from the engine's stator. They put out AC voltage and although I'm not familiar with Onans, think each should put out about 36 volts AC. If you have AC voltage on both of those wires, clean all the contacts and connect them back up and test the third lead on the regulator for DC voltage. Should be around 14v DC or so coming out. AC voltage in and no DC voltage out = bad regulator. No AC from engine= investigation into the stator. AC in and DC out = your problem is after the regulator and the electrical fun begins.

[Ed Kennell 39,288]

      Just to clarify where to measure, The two outside lugs on the RR are the AC wires from the stator where you should see the 30-36 VAC at 3600 RPM and it will vary directly with the RPM.    There is a second wire on the rear lug that is the trigger signal to the tachometer.     The center lug is the +DC to the battery where like John says,  you should measure 13.5- 14 VDC at 3600RPM .

Edited March 15, 2017 by Ed Kennell

[Sarge 3,464]

If you want to clean contacts in wiring , plugs and such get a can of DeOxit D5 , 5% solution . It's not cheap , but works far better than anything else I've ever used and will also protect from further corrosion . Caig labs has been making this stuff for years for electronics techs - nothing better out there other than full blown commercial stuff - and be aware , a little goes a very long way .

https://www.parts-express.com/caig-d5s-6p-deoxit-d5-spray-with-perfect-straw-5-oz-60th-anniversary--341-201

 

Sarge

[woodchuckfarmer 333]

Don't forget to check the 9 pin block.                                     Wayne

[cleat 6,735]

The 88 and 89 520's do not run the charge current through the 9 pin.

 

I have rewired all of mine this way. Just a wire from the regulator straight down to the starter solenoid with a 30 amp inline fuse close to the starter.

 

Gets rid of most charge issues.

 

You can just make out the sealed fuse holder in these pics tied to the dipstick tube.

 

 

Cleat

[Rich16 32]

Cleat - I posted about starting a bare p220 off an '88 and have figured it out (thanx to your help and others) and saw this post - can you tell me which line in the 9-pin connector (if it's even there) comes from the 12v DC off the rectifier to the battery?

 

The original engine wiring harness is still on and there's a red line with flat blade spade connector attached heading from the center 12v from the rectifier back into the wiring harness - I can't tell where the other end comes out and heads back to the battery?

 

Many thanks!

[cleat 6,735]

I assume it is the center wire on the latch side of the 9 pin as that is empty in mine because the 9 pin is not used for the charge circuit in my tractors.

 

Battery feed in from the solenoid / battery cable connection to power the tractor comes in on a red wire opposite the 9 pin latch on a corner.

 

Here are a couple of hand drawn pictures of the 9 pin connectors looking in from the connector side when unplugged from each other.

 

Wire colours are as per my machines so yours may differ.

 

I have used these pictures to wire all of mine.

 

520H Engine side.pdf

520H Tractor side.pdf

 

Hope this helps

Cleat

[Rich16 32]

On 10/8/2018 at 2:43 PM, cleat said:

I assume it is the center wire on the latch side of the 9 pin as that is empty in mine because the 9 pin is not used for the charge circuit in my tractors.

 

Battery feed in from the solenoid / battery cable connection to power the tractor comes in on a red wire opposite the 9 pin latch on a corner.

 

Here are a couple of hand drawn pictures of the 9 pin connectors looking in from the connector side when unplugged from each other.

 

Wire colours are as per my machines so yours may differ.

 

I have used these pictures to wire all of mine.

 

520H Engine side.pdf

520H Tractor side.pdf

 

Hope this helps

Cleat

Cleat - thanks so much for the wiring plug diagram - we both have the same system on the extra p220 I have from an '88 (or '89 but no later) but sounds exactly like yours and the one you retrofitted.

 

Down by the separate starter solenoid at the dipstick (which was missing when I got the engine) my wiring harness has two red wires - one with the fuse block and another without - both have the 'hoop' type end connectors but aren't hooked up. There's also a light blue wire with a clip connector coming out of the harness I presume goes to the small male clip on the starter solenoid.

 

From your pix it looks like one red goes to the hot side of the solenoid on the engine while the other goes to the separate starter solenoid - which one does the fused side go or does it matter? Can't quite get close enough in your pix to be sure.

 

Once the red hot lines are connected correctly does one of these come from the 12v red center line on the rectifier and will charge the battery once the main hot battery terminal is connected?

 

Enclosed is a pix of the orig starter solenoid with original wires still attached I'm going to get.

 

Getting close and couldn't do it without your help - really appreciate it!

[Rich16 32]

Oh Cleat - here's the starter solenoid pix I forgot to attach - Rich

[cleat 6,735]

Red wire with the fuse is the one from the regulator and connects to the battery cable at the starter solenoid.

 

Unfused one is tractor power and also goes to the same spot.

 

One of the wires from your auxiliary solenoid also connects there.

 

Light blue wire in harness connects to the small connection on the auxiliary solenoid and this will make it pull in when key is in Start position.

 

The other wire coming from the auxiliary solenoid connects to the small clip on the starter solenoid.

 

Here is the actual wire diagram. Wheel horse 520H wire diagram.pdf

 

Auxiliary solenoid is only used to reduce load on the ignition switch by the solenoid on the starter itself.

 

I have actually been replacing that with a nice sealed lighting relay.

 

Cleat

[Rich16 32]

Cleat - thanks so much!! Now I know exactly what to do and you are an invaluable resource.

 

Really really appreciate it!

Edited October 10, 2018 by Rich16
misspell

[Rich16 32]

Cleat - so far still frustrated trying to get it started - am installing new fuel pump which seems to be one of the issues (no gas coming up in filter).

Gravity feeding gas hasn't helped anything.

I ran a hot line from the ignition coil to where the + battery attaches to the starter solenoid.

When I do this I hear a uniform repetetive clicking sound coming from the carburetor whenever hot line is attached to starter solenoid???

Jumping the starter turns it over fine but she hasn't fired yet - haven't checked for plug spark and will have to start a full diagnostics I suspect.

Is the clicking sound from the carburetor normal?

Thanx so much!

 

[cleat 6,735]

Sorry for the delay in reply.

 

Nothing electrical in the carb so I can't help you there.

 

The condenser mounts beside the carb and would have power on it when you did this, maybe it is bad.

 

You did connect to the yellow + wire on the coil I hope.

 

You can try this to troubleshoot the ignition system. Troubleshooting the electronic ignition module for P Series.pdf

 

Cleat

 

 

 

[Rich16 32]

Thanks again Cleat!

Yes - attached yellow wire on ign coil to + battery connection I hooked up on starter.

I wondered if the clicking sound I could hear thru the carburetor was the spark plugs firing without the engine running? When I first heard the sound it was odd.... and an ear to the carb throat sounded like where it was coming from but will investigate further.

The troubleshoot guide is fantastic - should lead me to the answer.

Again really appreciate your willingness to help!

 

[Rich16 32]

Cleat - Hurrray! Success!

My alligator clips/wires weren't the best so I went to an auto parts place and bought new wire/new alligators and re-soldered everything & hooked back up.

Then I realized the fuel pump probably wasn't up to the gas line sitting in my gas can a few feet below the engine.

So I tilted/sat the gas can about equal to the fuel pump height and then 'old schooled' it.

Sucked on the line until gas came out and hooked it up to engine fuel pump - still can't believe I did this

One touch on the starter and she purred to life - more correctly jumped to life!

It's amazing how balanced these engines are - sitting on a small piece of 3/4 plywood on a cinder block and no problem running on it not fastened down - amazing.

I played with it for some 30 min & it ran flawlessly and I couldn't be happier!

I know it had everything to do with you telling me exactly how to hook everything up & can't thank you enough!!

There's nothing like helpful encouragement when you don't know what you're doing.

Best Cleat!

    Rich

[Ed Kennell 39,288]

Great news Rich.  Thanks for the report.   I know Cleat is just as pleased as you are to get her running.   

[cleat 6,735]

Good to hear.. And I am more than happy to help where I can.

Yes, these engines run smooth. That is one of the things I like about the Onan engines.

 

Cleat