1988 520H not turning over

[RocTeach 0]

Hoping for some help, advice, anything to make my months-long mission to get my 520-H running a success story.

Inherited the tractor from the previous owner of my home. He rarely used it -- preferred his zero-turn -- and advised that I always keep it on the float charger when not in use. I used it for one month's worth of cuts last summer, and then began having problems. At first, the engine was surging. It would fluctuate from high to low rpm with the choke off. However, if I played with the choke (thereby getting way too much fuel and oil into my system), it would run for at least the rest of that cut. After having to keep it running with the choke, it eventually stopped turning over AT ALL.

I did the general maintenance: changed both plugs, dropped the oil, drained the fuel, replaced the fuel filter, removed all of the visible (and accessible) electrical connections and cleaned them up. Bought a new battery as well, and the tractor started right up. Sounded better than ever. For one cut. By the end of the cut, I had to start messing with the choke again to keep it running.

So, I cleaned the carb, replaced the fuel filter (because it was making a strange knocking sound), cleaned the (new-ish) plugs, bench tested the solenoid, changed the solenoid. When I connected the battery and went to start, I got (what sounded like) very little power to the starter. Loud clicking/rattling sounds ensued, so I brought the batt to Autozone to check the juice. It was at 50%, and it was only one month old. They charged it, and when I reconnected the batt...nada. Nothing. The same old clicking, metal-thrashing-like sound/s. I've tried to jump the solenoid directly -- same result. I've bypassed the solenoid and put all connections directly to the starter -- same result. I've downloaded as many Wheel Horse PDFs as I could find, including the demys guide. Now, I'm thinking about the regulator. Thinking about it as it sits in front of my laptop. It's an Onan 14v 20a. Two ACs and one B+ connections. I'm really hoping it's not the stator and/or the starter. So, any advice on how I should proceed would be greatly appreciated. I have experience with small engines from my years taking apart and racing dirt bikes, but things are just a bit more challenging to access with this beast. But, from EVERYTHING that I have read/heard, a working/running WH will be well worth all of my effort.

Sorry for the long post. I am an English teacher : )

-O
 

Edited July 16, 2015 by RocTeach
Spelling

[lynnmor 8,114]

You need to test the charging system first.  Charge the battery and get it running then follow the instructions. manual
 

[gwest_ca-(File Mod) 11,769]

The charging system has nothing to do with the starter. All the regulator does is rectify the AC current the stator produces and when the voltage reaches the 14.4 volts it limits the current so the battery is not overcharged.

If you connected both cables directly to the starter and it does not run the starter is the first problem. Power to the starter terminal and the ground to the case of the starter.

If you connected the ground cable somewhere other that the starter housing the starter grounds could be the problem.

Remove the spark plugs to eliminate compression and see if you can turn the motor over by hand at the flywheel. If you can that removes the chance of a mechanical problem.

I don't know where the battery ground cable is connected to the tractor chassis. I like to see it bolted to the engine because the starter is the single largest load the battery will ever see. Then add another ground cable from the engine to the frame for the lighter electrical loads.

Garry

Edited July 16, 2015 by gwest_ca

[546cowboy 302]

Is your battery ground cable grounded on one of the engine mounting bolts? If not do that.
If your battery is fully charged hook a voltmeter to the connection at the solenoid and turn the key to start and watch the voltage on the meter. If it drops below 9 volts you have a problem in the starter or a bad battery. You did not say weather they load tested the battery.
This can also be measured with an amp meter, if you have one that  can be just held on the wire, at the battery cable. If it shows an excessive draw it will be the starter.
Until you get it to start and run, you can't test the charging circuit correctly. The charging system won't keep it from turning over on it's own.
 

[Ed Kennell 43,256]

All of the above is good advice. I  also routinely unplug and replug all the connectors and the three fuses  at least three times to clean the contacts on my '88 520.  I have found this resolves most of the electrical problems.  Of course replace the fuses if they are open or if the legs are corroded away.   

[953 nut 62,445]

   The previous owner sure was nice to give you his Wheel Horse!

 It sounds like you have two unrelated problems. The starter Bendix drive could be hung up or the brushes on the starter may not be making a good connection due to dirt build up or a bad spring. Pull the starter, clean it as best you can and bench test it. If it won't work you may want to take it to a good starter shop.

The need to choke the carburetor could be caused by lots of things. If you have been using gas with ethanol in it I would start with a new fuel line, it could be coming apart inside causing you a headache. To find ethanol free gas go to buyrealgas.com  and put in your zip code. Another place to look could be the fuel cap, it has a vent and if that is plugged the tank will be under a vacuum as fuel is used. Once you overcome the starter issues try running with the cap a little loose and see if the problem goes away, if so buy a new fuel cap.

Hope this helps.

[bmsgaffer 2,054]

Welcome!

I am surprised no one has mentioned this already, but we want pictures!

Give us lots of good pictures, sometimes the experienced people on here can catch something visual also. (And we like looking at tractors...)

Boy I wish you had never said you were an English teacher. I am self conscious just posting this terrible excuse for written word!

[GMan 82]

Guys, I don't normally reside in the WH world (although I like them a lot), rather the JD world. I have over the years owned a lot of JD's with Onan engines. The Onans are famous for developing "surging" problems via two issues. First the idle jet column inside the carburetor (especially after having sat for long periods of time) tends to get plugged up. It is a tube that is about 2.5-3" long and has several very small holes along it's side and one hole on the bottom. i have and use a set of welding tip cleaning wires to clear these holes. This tube has to have all holes clear to avoid the surging issue. Secondly the intake manifold on these Onans is made in two pieces. The gasket OEM material used to seal both halves deteriorates with age and can cause the surging by allowing the system to suck air thus the need to run with the choke partially closed. This is not difficult to repair, rather it is time consuming. The manifold must be removed, split apart, cleaned thoroughly, and resealed with a suitable sealer that is impervious to gasoline. 

Now for the starter issue. On the JD's, John Deere changed the later tractor circuits on Onan powered tractors to a system that got rid of the separate solenoid that was used to latch in the starter bendix. This new system used the contacts of the ignition switch to pull in the new starter mounted solenoid. With time it was learned that these ignition switch contacts to prematurely fail. The result was for the starter mounted solenoid was only partially pulled in which resulted in the "clicking" sound when the key was turned. JD then offered a separate relay kit that could be installed on the tractors that relieved the load on the ignition switches by latching in this relay (and carries the current load) allowing the starter solenoid to be adequately pulled in as the tractors were being started. 

You can view the idler jet within the carb (ref: Item number 5 that I referred to above) by this link. jd carb.pdf .......................Hope all this helps..................Gary H. 

Edited July 16, 2015 by GMan
spelling correction

[RocTeach 0]

I appreciate all of the prompt feedback and advice! I just got in from work, so I'll go take some pics and maybe a video as well, and get those up here soon.

In response to some of the advice:

• I'm going to try power directly to the starter one more time, and see if anything changes.
• The fuses all look good to the naked eye, and there is continuity in each; however, I may end up getting a few of those next time I head to the parts shop.
• The battery has not been load tested, yet.
• How do I manually turn the engine over at the flywheel?

Thanks again! 

[gwest_ca-(File Mod) 11,769]

Two hands on the flywheel screen should turn the engine in the normal clock-wise direction if there are no mechanical problems - with the spark plugs removed to eliminate compression.

If you have a voltmeter connect it to the battery and observe the voltage before and while cranking or trying to run the starter. That is a load test of sorts.

Garry

Edited July 16, 2015 by gwest_ca

[bmsgaffer 2,054]

You will have to take the flywheel screen guard off on the Onans to get to the part you can spin. On the old kohlers the spinning flywheel screen was exposed but the onans its guarded.

[gwest_ca-(File Mod) 11,769]

Can you tell I don't have any Onan's?

Guess the only way to turn it over by hand would be to apply the pto clutch and turn the pto counter-clockwise.

Garry