Wheel Horse 520_6 4.30 star(s) (3)

Back to the Red Machine 520 H
Model Year: 1992

Just picked this up a couple of days ago. Someone traded it in on a zero turn mower. 1992 vintage WH 520 H with only 720 hours on it. Gave my JD 318 to my father-in-law hope that was not a mistake. So far this 520 H runs like a bear. The Onan 20 hp engine has more than enough power to run attachments. I really like the full featured dash with tachometer, oil pressure, hour meter, fuel and voltmeter gauges that all light up! Has a 42" rear discharge deck. Also is equipped with hydraulic deck lift and grease fittings galore! So far it seems to run very well but am going to get a knob for the steering wheel, had one on the John Deere 318 and I miss it.

Pros: Nice cut, plenty of power, well featured dash and arm rests on seat.
Cons: Hydro-stat needs foot controls and drinks gas!

Photo Uploads:

Toro Wheel Horse 520H 1991
Model Year: 1991

I bought my Wheel Horse 520H (with Onan 20hp-twin performer engine) new in 1991 with a 48-in. side-discharge deck and have used it every season to mow my couple of acres. I've made several changes over the years that made it even better than the original. The turf tires kept going flat, and they made it steer very hard so I replaced them with cleated tires in the rear and some triple-ribbed tires in the front (Gemplers has them). These front tires made it feel like I had added power steering, and they reduced the turning radius because of the better grip. Some of the idiot safety switches went bad (seat switch, neutral switch, blade engaged switch, etc.) so I have eliminated a lot of them. The original blades would leave non-mowed strips after a few sharpenings (because they get a little shorter each time), so I replaced them with Gator mulching blades, which are slightly longer so they overlap more. They didn't use a primer so my paint was falling off in large patches. I stripped, primered, and painted all of the sheet metal parts with Rustoleum (apple red is a little brighter than the original but looks really nice). The Onan's coil got real weak a couple years ago and I was shocked at the price for a replacement. I ended up buying a pair of $12 automobile old-style coils, mounted them to the air box, and wired the primary sides in parallel. Then I had more spark than necessary. It was so easy to start, but caused severe pre-ignition when I'd load the engine heavily (like mowing tall grass). I found a cure though. The original spark plug gap spec was like .018", which seemed very tight to me. I theorized that if I made it wider, it would cause the spark to happen a little later in the power stroke. Turns out I was right. I have opened the gap to .060" and it still starts right up and has no more pre-ignition problems. As with other Onans, mine developed a loose intake valve seat (rear cylinder) due to over-heating. This must have been going on for a couple of years before it started making noise. Last spring, I discovered the valve wasn't even closing all the way, so I readjusted it and it worked fine for the rest of the season. This spring, it started making a loud ticking sound (first time I got it hot) so I tore it down to investigate. That's when I discovered the loose valve seat. It had hammered itself into the aluminum block about .050", which explains why I had to readjust it last year. I researched the cures to repair this and didn't like the options. A lot of fellows were replacing the whole engine because of the cost of the repair. This was not a option I could afford, so I decided to try something different. I found out that Loctite makes a product that is used to attach carbide tips to boring bars, so it can handle the heat. It's called Loctite Black Max 380, and they get $36 for a little 3 gram tube, but if you shop around you can find it a lot cheaper. Midway USA (gunsmiths use it too) has it for $5.99 a tube. So I got some and tried it to glue my valve seat. The bore in my block was still straight and I measured it at only .001" bigger than the OD of the seat. I cleaned and shined up the bore and the seat, and then cleaned it with spray electronic cleaner, then applied the glue to both parts with a cotton swab. Tip: the plastic cap on my CRC electronic spray can was the perfect size for pressing into the valve seat and it gave me a handle to use for inserting it into the bore. This glue is like weld-in-a-tube. Some claim you have to get bonded parts red hot to separate them after it has cured. Make sure you use latex gloves when you handle it. I let it cure for 24 hours. I reassembled the engine the next day and have given it a workout for several weeks with no problems. Can't help thinking about all those discarded Onan engines that could have been repaired for $5.99 and a little work! So that's my story. I hope this helps somebody out, and saves them a bundle!

Pros: Powerful, solidly-built tractor, that will serve you well for many years if you maintain it.
Cons: Rear cylinder cooling fins on Onan easily plug with grass clippings.

Photo Uploads:

Wheel Horse 520H
Model Year: 1996

I bought this tractor to cut my grass and to keep the woody parts of my property clean of underbrush. I had planned to buy a larger tractor later on so I would not have to use this small tractor as a bush hog but things didn't work out too well in that area. I have called on this machine to do more than it should many times and it has always come through for me. It has kept my woods free of underbrush and with sharp blades it still keeps my lawn looking good all year. I have a couple of trailers I use to haul wood, dirt, bark, gravel or what ever else that needs to hauled around my place. I also pull logs and blow downs to burn piles when it's clean up time or to the wood pile for processing at the splitter. The tractor is rock solid, tough as nails and has met all expectations.

Pros: Powerful, pulls good for it's size, easy and comfortable to operate.
Cons: Onan engine burns a lot of gas, mule gear is in a position that can be easily banged around. The hydraulics are a little under powered for my use but about right for this sized tractor. Mowing deck would be better if it was a mulcher but it's great in the woods.