Chasing 520H Electical Gremlin - Introduction

[Kissinger_520H 3]

Greetings to the group! I'm new here to the forum and wanted to introduce myself. I live in Western PA and about 6 years ago I moved from town to the country and went from a half acre yard to a 40 acre parcel. Fortunately the majority of my property is wooded but I've still got a fair amount of grass to cut so back in 2017 I bought myself a 1989 520H knowing almost nothing about them aside from the fact that they would spin a 60" deck and that sounded good to me. I found a nice low hours machine with a 60" deck, snow thrower, and cab. I've never used the snow thrower and finally sold the bulky cab recently. My original 60" deck was starting to have some structural issues so I picked up a second deck locally and intend to have the original repaired soon. My tractor had about 500 hours when I bought it and has about 800 now, though I suspect that over a hundred of those occurred with the key left in the on position at some point as my dutiful service records don't account for that gap. But that's another story. 

 

I haven't had any real issues with the tractor and run strictly ethanol free fuel. I change the oil, fitler(s), plugs etc annually and she always fires right up and is ready to tackle my property. But lately she's developed a couple issues that I'd like to get sorted asap. 

 

First, the charging system seems to be on the fritz. I'll fire the tractor up and the charging indicator will show about 14 at running RPM and all seems well until it randomly decides to jump up past 16v. This could happen quickly or after 30 minutes of mowing. I have removed all the connections at the voltage regulator and cleaned the connections and coated in dielectric. This seemed to improve the performance initially but quickly returned the same thing. I have checked my grounds, checked and cleaned all my fuses, disconnected and employed the same dielectric but no luck. Before I just order a new regulator, I wanted to see what the group is thinking. When it runs up past 16 I'll switch the lights on and it'll come back down and a few minutes later it will drop to zero. At that point I'll switch the lights off and it'll go back to normal for a random amount of time before running back up over 16. 

 

Second, and this one is really perplexing me. I don't recall when this started but the oil drain pipe used to point slightly upward in a snug position and when I wanted to change the oil, I'd pull it down, remove the cap and drain the oil. Now it doesn't sit snugly upward for more than a few minutes of running and it just flops loosely down to the lower position. I frankly don't understand why it doesn't leak oil but it sure doesn't seem to as I never see any indication of it and I not only check frequently but I keep the tractor very clean so it would be obvious. Is this possibly normal? Is there a way to tighten this? 

 

Third, I checked my air filter recently after less than 10 hours since installing a new filter and pre-filter and found a thick oil residue all over the housing. I don't recall this before. I tend to replace both filters every year before I put the tractor up for winter with a new main filter and a new prefilter soaked in a tablespoon of engine oil and wrung out. 

 

Aside from these issues, the tractor is a beast and has continued to impress me with what it's capable and willing to do. I do wish the deck could raise up higher for brush cutting but all in all she's a great rig and capable of climbing some seriously steep slopes and never skips a beat or complains about the demands I place upon her. 

 

I hope to get these issues sorted asap so I can get back to enjoying the old Wheel Horse without fear of doing any unnecessary damage. 

 

Thanks, 

 

Chris

 

 

[Ed Kennell 38,158]

to the   Chris.          Thanks for the great intro.    Sounds like you're doing some good maintenance and trouble shooting.

 

The charging issue.....Make sure the RR has a clean ground.  It is grounded thru the bolt that fastens it to the tins.     You could add a ground wire from that bolt to the neg battery post.

Any sign of heat in the 9 pin molex connector?           

 

The oily filter....clean the crankcase breather filter.

 

The floppy drain pipe....next time you drain the oil,  you could remove the nipple and elbow and add a lock nut to the elbow.

 

 

[lynnmor 7,305]

The hour meter is turned on by the oil pressure switch so it will not operate unless the engine is running.

Yes, check the grounding at the regulator bolt, cheap regulators are available at the usual auction and jungle sites.

Be sure that the rubber grommet is in place that seals the space between the oil filter and the engine shroud.

At 800 hours it is due for a valve adjustment.

Often with a pre-filter the condition of the paper air filter can't be determined, place a light inside the filter and compare it to a new one.

It is rare for the breather to be plugged, perhaps the original owner assembled it poorly.  Hopefully the engine is in good condition, check the compression to be sure. A low compression reading could be the cause of the oil problem.

The oil drain often is an issue.  I remove the pipe into the engine and replace it with a new one and seal it with high strength red threadlocker after cutting new threads with a pipe tap. Of course the tractor needs to be tilted as required when tapping, then cleaning and installing the pipe, you want no oil contamination on the new threads.

[Kissinger_520H 3]

5 hours ago, Ed Kennell said:

to the   Chris.          Thanks for the great intro.    Sounds like you're doing some good maintenance and trouble shooting.

 

The charging issue.....Make sure the RR has a clean ground.  It is grounded thru the bolt that fastens it to the tins.     You could add a ground wire from that bolt to the neg battery post.

Any sign of heat in the 9 pin molex connector?           

 

The oily filter....clean the crankcase breather filter.

 

The floppy drain pipe....next time you drain the oil,  you could remove the nipple and elbow and add a lock nut to the elbow.

 

 

 

Hey Ed! Thanks for the welcome and for weighing in here as well. 

 

So as for the RR, I removed it this evening, cleaned it up, cleaning the mounting area, the bolt and reinstalled with a bit of dielectric. I'll test it in the a.m. I like your idea of adding an additional ground wire and I think I'll do that. I think I've got a few spare ground straps that they sell at NAPA and I'll bet that would perfectly for this purpose. 

 

As for heat at the 9 pin molex connecter, forgive me but I'm not certain what that is. BUT, the white connector to the RR does look a bit brownish and that is suspicious. I melted my 30AMP fuse up front last year due to a grounding issue that I've since sorted, replaced the fuse etc and all seemed fine after that. Perhaps related, perhaps not. 

 

As for the crankcase breather filter, can you point me in the right direction for that? 

 

I like your solution to the floppy drain pipe. While Lynnmor's solution sounds like a solid permanent fix, it also sounds like it would be much simpler with the engine removed from the frame and I'll wait until such a time as I've got a good reason to pull it to go that deep. 

 

One other curiosity that I forgot to mention. Perhaps around the same time my voltage went haywire, I noticed another peculiarity as well. When I shut the tractor down, the tach remains at whatever RPM is was holding before shutdown. If I flip the key back to the position before ignition, the tach will drop back to zero otherwise it simply sits wherever it was left until I run the tractor again. 

 

 

3 hours ago, lynnmor said:

The hour meter is turned on by the oil pressure switch so it will not operate unless the engine is running.

Yes, check the grounding at the regulator bolt, cheap regulators are available at the usual auction and jungle sites.

Be sure that the rubber grommet is in place that seals the space between the oil filter and the engine shroud.

At 800 hours it is due for a valve adjustment.

Often with a pre-filter the condition of the paper air filter can't be determined, place a light inside the filter and compare it to a new one.

It is rare for the breather to be plugged, perhaps the original owner assembled it poorly.  Hopefully the engine is in good condition, check the compression to be sure. A low compression reading could be the cause of the oil problem.

The oil drain often is an issue.  I remove the pipe into the engine and replace it with a new one and seal it with high strength red threadlocker after cutting new threads with a pipe tap. Of course the tractor needs to be tilted as required when tapping, then cleaning and installing the pipe, you want no oil contamination on the new threads.

 

- So it seems that the hours cannot count without the engine running. Very interesting. The reason I had surmised that I had done some such folly is that I keep a log in my owners manual of every service which I generally perform at the outset and the end of each season. The log includes a date as well as the engine hours. When I look through the log, I can see that average about the same hours every year more or less except for 1 year which I somehow doubled my average. 

 

- Reg bolt, checked, Reg cleaned and ready to test in the morning. 

 

- I'm not sure which grommet you're referring to. Will I need to remove the engine oil filter to check this? 

 

- I ride and restore vintage motorcycles and have done dozens of valve adjustments, but as I've yet to perform this on the 520, is there a resource that I can read, watch, etc to familiarize myself with the procedure?

 

- The air filter can't have more than 10 hours on it and my conditions are probably slightly worse than average. I'll try the flashlight and see how it looks. 

 

- I can't speak to the assembly of the breather, I've never been into it. But from what I've seen of this and other 520's, I'll say that this one does not appear to have been monkey'd with much at all. 

 

- Proper technique for checking compression? 

 

- I'm going to dig into the drain pipe and see what I can do without having the machine laid up too long during my cutting season. Our grass is growing fast and thick this season. 

 

One more question. How is it that this drain pipe can be so loose without leaking? That one has had me scratching my head for a while now. 

 

Okay that's all for now. Thanks for all the help so far and I have to admit that I have developed a genuine fondness for this old tractor and hope to keep it running well for many years to come! 

 

Good Night! 

[Kissinger_520H 3]

I meant to add this to my last post but forgot so here they are. 
 

This at least looks original to me. If 12 88 is a date code, that would seem consistent with a 1989 520H. 

[Ed Kennell 38,158]

54 minutes ago, Kissinger_520H said:

 

As for the crankcase breather filter, can you point me in the right direction for that? 

Onan P218G Crankcase Breather Valve Issues - Engines - RedSquare Wheel Horse Forum

[lynnmor 7,305]

Your early 520H might have a 30 amp fuse in a wire to the starter, that saves the fuse block from a heavy load. Newer models passed everything thru a 9 pin connector located near the battery and that caused problems with a burned connector.

Here is a link to the grommet around the oil filter, it just slips into place.  Some brands of oil filters may be a bit smaller and not have a firm grip, allowing the grommet/gasket to fall out.  I use only Onan or Fleetguard oil filters.  Working the engine hard with a missing grommet will result in a large leak of the cooling air and possible engine damage.

Download the Onan Service Manual and the Demystification Guide, they will be a big help.

You will need a compression tester, it just pushes into, or screws into, a spark plug hole while cranking the engine..

After the compression is confirmed to be good and you are ready to adjust the valves, report back.  It is a rather big deal to disassemble things and you may as well do some other maintenance in the process.

 

[Kissinger_520H 3]

Well it took me a few days. I've been chasing a timing issue on my 1968 R50/2 and then while mowing on Tuesday had issues with my 60" deck. Seems like it's just one thing after the next. But I'll get back to that.

 

So after I cleaned, coated with dielectric and reinstalled my regulator, the charging system is now functioning perfectly and I'm very pleased to report it! Thanks for all the tips. I had cleaned the connections but hadn't thought of removing the unit entirely to improve the grounding which was clearly the issue and while I should have thought of that, I didn't! So thank you! 

 

I also removed the air cleaner cover after another several hours of run time and there's no oil or much of any dust/dirt  in there so I'm not sure what was going on there before but I still intend to clean the breather and check for proper assembly etc. 

 

So back to my deck issue. While mowing along one of my banks I noticed that the deck was no longer responding to the hydraulic. So I hopped off and got down to see that the arm that fits into the slot in the deck had slipped out leaving the deck in the fully lowered position without means of raising it. So I drove to a flat area, lowered the arm to align with the slot and tugged the deck back into place wondering what happened to knock it out. I went back to cutting and shortly after noticed the deck had once again dropped. This time I hopped off and saw that the arm hadn't slipped off but the upper trunnion chain attachment was lying on the top of the deck and it had come loose from whatever it attaches to above. Ugh! So I drove back over to the barn and figured this was going to take some time to figure out.

 

Installing and removing this giant and very heavy deck is usually not too much trouble with the help of the hydraulic lift, but without it, the attach-a-matic isn't so easy. I eventually got it disconnected with the help of a 2x4 to remove the tension on the attach-a-matic and then just backed the tractor off the deck to get a better look at the upper trunnion. I then realized that there are 2 arms that the hydraulic controls and since the attachment had fallen off, I had no clue which one it was attached to. I looked for indications of the attachment, worn face, worn holes etc and it at least appeared that something had been attached to the upper arm but this left me wondering what the lower arm was for. I experimented with watching both and realized that pulling the hydraulic lever backward raises the upper arm and lowers the lower arm. So they're reversed and I've always raised the deck by pulling the lever back so this indicated that at least previously, the upper arm was where it was attached. But then I get to decide in which of the 3 positions and on which side. The gap was too tight on the right so I decided it must go in from the left and the rear most hole looked to be slightly more worn so I decided it must attach there. Now the issue is that the cotter or whatever secured the attachment had clearly sheared off and would need to be replaced. I was surprised to see that the attachment shaft was not long enough for a washer to be used behind the cotter which seems odd and prone to failure with each act of raising and lowering ultimately placing a portion of the force against the cotter. I couldn't believe it had lasted this long unless I'm missing something. 

 

At any rate, I took the opportunity to flip the deck upright, remove the blades, scrub the entire deck clean, sharpen the blades and hit each grease zerk before getting it ready to reinstall. I also couldn't help but notice that the rack of the deck that moves up and down looked a little out of whack and wondered if it got bent somehow and that is what allowed the arm to slip out of place. At any rate, I pulled the tractor back over the deck and got it hooked back up. I have always felt that the deck doesn't lift as high as it should, and I think I mentioned that in my first post. So I took this opportunity now that I was aware of this upper trunnion adjustment bolt to tighten the bolt to adjust the lift height. I tightened and tested until I felt the deck pin itself against the stops at the top, which it had never done. I wasn't sure if this was too tight so I then backed it off until it fell slightly short of being pinned. At this point I felt that the rear deck level adjustment required a bit of fiddling and wondered about the lift arm peg. While raising and lowering the deck it appears that the arm wants to walk out slightly and not keep the peg fully seated in the slot. It puzzles me that unlike the other attachment points, there's no hole in the peg to secure with washer and cotter. 

 

Unfortunately, while my tractor came with a manual for the tractor, motor, and many attachments, it did not include a manual specific to the 60" deck. Is one available online perhaps that I could print out to add to my 520H folder? Also, after reading through my exploration into the deck and the trunnion attachment, does it sound like I'm on the right track or can someone weigh in that perhaps I'm missing something? I have the chain attached to the rear-most hole in the lower lifting arm and the bottom link of the chain. What puzzles me is that the hydraulic moves through almost 75% of it's distance before taking up the slack of the chain and it seems like an odd design if in fact it's set up correctly.

 

Sorry for the lengthy post but if anyone has read this far, thank you and I'm very glad to have found this community. I'm so glad my tractor is back to steady reliable charging and also glad to have learned so much from the group already to help keep my tractor running strong. I still intend to perform a compression test soon to get an idea of the health of the motor. From the power this thing produces, I'd be surprised to find low reading but we'll see. 

 

Okay that's all for now.

 

Chris

[lynnmor 7,305]

A manual for your deck can be found in the manuals section.  I suggest using it to install and adjust things starting from the beginning of the instructions.  Manuals can also be found on the Toro site if you have the model number.

[gwest_ca-(File Mod) 11,041]

 

[Kissinger_520H 3]

Lynnmor,

 

Thank you. I found the applicable manual for my 60" deck which seems to indicate that it is a newer model than my '89 520H as my current deck has the anti-scalping front corner rollers whereas the original 60" deck did not. So I've printed the manual and it seems to indicate that I've attached the upper trunnion correctly but it also indicates that there should be a hairpin cotter and washer on the lower lift arm and this was part of my initial question regarding this arm slipping out. I see no hole in the arm to allow for such a cotter and now I'm scratching my head about how this could be. I'm going to go out to the barn and see if I've somehow missed something here but that would surely solve my issue of this coming undone during operation. 

 

Will report back. Very glad to add this manual to my files. Thanks!

 

 

[Kissinger_520H 3]

Well I took some time yesterday to tear down my old 60" deck to evaluate the components and see if there's any other differences between this older model and the one currently installed. I also pressure washed then entire old unit in preparation to drop it off at local repair shop for evaluation. If I can get it properly fixed, I think I'll do so and offer it up for sale afterwards. If he thinks that it's too far gone, I'll salvage the good parts and scrap the deck. The corner where the adjustment arm mounts has completely rotted through so that section will need to be completely replaced as well as a forward section that has several holes punched through. 

I took my current deck back off the tractor and swapped a few parts in from my older deck which were in better condition and took the opportunity to crawl under the tractor and get my eyeballs on the lift arm. Eureka! Sure enough there is a hole in the arm but it was fully packed with dirt/grease etc that it was practically invisible to the naked eye until I pushed a new hairpin cotter through it. Okay so now I'm getting somewhere. Reading through the removal instructions indicates that one should turn the wheels fully the left and pull the deck out from the right side but I can't see as to how this is doable as the rear wheels of the deck won't come close to clearing the rear wheels of the tractor in any position. So as usual, I just backed over the deck for removal and pulled back over it for installation. It would be much preferred to be able to slide it in and out but unless I'm really missing something there, it just won't fit (and yes I've got the upswept front axle). At any rate, I lowered the lift arm, pulled the deck slot into position, realized you must install the washer and cotter first, then lift the deck and attach the attach-a-matic brackets. This worked perfectly and the deck functioned better than ever! Success! 

 

Now I'm off to test it out and will report back. It may just be me, but cutting with a sparkling clean deck and freshly sharpened blades is a real treat. The hum of the deck sounds stronger and more powerful when it's clean and I'm looking forward to enjoying a few hours of cutting today. My second daughters 1st birthday party is here at the farm tomorrow so I'm going to spruce the place up with a fresh cut. 

 

Thanks!

 

Chris

[lynnmor 7,305]

With the forward swept front axle and standard size tires the deck will slide in, just don't expect it to go in a straight line.  You need to do a bit of a dance twisting this way and that way, you also need to play with the mule drive as you go along.  As for the washer and cotter, we are likely the only two people that uses them, I have read often from folks that just ignore those parts.  Did you follow the instructions on setting the scalp roller height?

[rick 233]

I had to put a second washer under clip pin on the lift arm, to keep it off the center pulley zerk.  After puzzling over two rubbed of zerks, a light came on between my ears!  Not a 60" deck, just a 48" deck.

[Ed Kennell 38,158]

40 minutes ago, rick said:

to keep it off the center pulley zerk.

I always remove the zerk and replace with a set screw.

[Kissinger_520H 3]

16 hours ago, rick said:

I had to put a second washer under clip pin on the lift arm, to keep it off the center pulley zerk.  After puzzling over two rubbed of zerks, a light came on between my ears!  Not a 60" deck, just a 48" deck.

Hmm I don't recall seeing an interference here but I'll give it a good look before I run the machine again. 

 

On 7/21/2023 at 3:21 PM, lynnmor said:

With the forward swept front axle and standard size tires the deck will slide in, just don't expect it to go in a straight line.  You need to do a bit of a dance twisting this way and that way, you also need to play with the mule drive as you go along.  As for the washer and cotter, we are likely the only two people that uses them, I have read often from folks that just ignore those parts.  Did you follow the instructions on setting the scalp roller height?

I had clearly gotten away without using it for a while but it seems like something changed that was causing it to slip out of position and drop the deck. I removed the deck brackets from this deck and the brackets from my back-up deck and they were practically identical and what I thought was a bent center bracket seems to be a factory design as they are both showing the same angle. But be that as it may, it seems that the arm was slipping out and I reached under the tractor and tugged on the lift arm and there's no play so I don't think the arm is the issue but at any rate, with the big washer and hairpin cotter in place, I won't have to worry about that again! I also like that now the deck goes all the way up instead of only partially as it always had. As for the scalp roller height, the deck has a decal that indicates to place them at 3/8th" above ground level at the desired cutting height. I wonder if they were a bit too low and the pressure on them was driving the deck off the lift arm previously. But from memory they rare touched the ground and mostly just hung there while mowing unless I go over an irregular section of ground. 

 

At this point I need to do a bit of fine tuning to the rear leveling bolt and I wanted to be sure that this is done with the deck in the middle position on the height selector and in the lowered position. Correct?

 

 

[rick 233]

That is correct on the narrower decks, I don't have a 60" deck so no manual to check .

[Kissinger_520H 3]

4 minutes ago, rick said:

That is correct on the narrower decks, I don't have a 60" deck so no manual to check .

So this is the description of the leveling adjustment and I’ve gotta admit this makes no sense to me. 

 

“Adjust distance from surface to blade tips equal to 1/8 inch front high.” 

 

I don’t know who wrote this but I can’t quite imagine what this is indicating. I would think you would simply measure the front of the blade tip to the ground and the rear blade tip to the ground and adjust until they’re the same. But setting them 1/8” from the surface seems extremely low for any height setting. 
 

Am I missing something?

[Kissinger_520H 3]

[Kissinger_520H 3]

Okay thinking this over for a while has me thinking perhaps this means to set them at equal height to the front being 1/8” higher than the rear. 

[rick 233]

Yes, from equal height front and rear to front being 1/8" higher.  Be sure the deck lift arm is lowered all the way so it isn't influencing the deck carriage.  It's best to use the same tip for both measurements. 

[Kissinger_520H 3]

Well I've done some adjusting and think I've got it nicely leveled when in the lowered position. It seems the lower trunnion nut when tightened raises the front of the deck. It was actually almost perfect before I touched it so I slightly tightened up the nut and brought the front up 1/8th". 

 

Now when it comes to leveling the lifted deck, that is a different story. The manual says that the bumpers should be set at the lowest setting and any adjustments necessary made to level the lifted deck. So with both bumpers at the lowest setting and the deck lifted, the right side against the bumper and a few inches higher than the left which cannot reach the bumper. It took me a minute to realize that the top of the deck on the left side was bottoming out against the left side of the attach-a-matic front attachment. On the left side, there's an arm that flips down when the carriage is secured and it hangs down several inches. So when I raise the deck, it runs into this arm and keeps the left side from hitting that bumper or going as high as the right side. I can lower the right side bumper to even things out but that ultimately results in a deck that doesn't lift as high but as I see no means of adjusting that mounting switch arm, this seems like the only option. That said, I can clearly see wear marks on the bumper towers that show the deck was able to be raised higher in the past which has me puzzled.

 

I may be overthinking and analyzing this but this is just how my brain works. I want it to be perfect and I want to fully understand the manner by which it was designed to function. So for anyone following along, thank you! 

[lynnmor 7,305]

My 60" deck manual says this:

 

I adjust it to level when in the desired cutting height,

Typically the blades are adjusted to 1/8" low in front to avoid additional cutting at the rear.  The manual for some 42" decks says to adjust to the front high 1/8", I don't know if that is a typo.  Since most Wheel Horses cut too low even at the maximum height setting, I adjust to level to get as much height as possible.