20hp twin cylinder Onan

[Jon Paulsen 291]

Hello fellow jockeys, is this a super reliable engine? I understand the B&S is pretty good at living forever, but never even laid eyes on an Onan. I have a line on a 520H with a 42" snow plow that had the plow frame narrowed to fit this model. Price is high, but sent a feeler to see if he wants to come down. I have to add 6 to 8 hours of my time to go get it. Maps say 1 1/2 hourish, but old Jeep + trailer would take longer. I will hold and look elsewhere unless this is a sizzling hot setup. I don't NEED a snow plow, but wants can outweigh needs 

 

All opinions on this engine, the 520H and the stock hydro gearbox would be much appreciated. 

[lynnmor 7,730]

The fact that the owner cobbled up a fix for the wrong plow speaks volumes.  There is a proper plow and an extension for plows that were made for shorter series tractors.

 

All engines have their strengths and weaknesses and Onan is no exception.  Given proper care and maintenance, an Onan will run thousands of hours, in the hands of the usual clueless homeowner they can be destroyed like any other.  Problems that might be found in these engines and not in other brands are; flyball spacer coming loose, intake manifold leaks and valve seat failure. 

 

Ask the seller when he last adjusted the valves, changed the oil and why is the gasket around the oil filter missing.

[Jon Paulsen 291]

Thank you @lynnmor !!! I've only worked on 2 strokes, B&S engines, and ratty dirt bikes. Seller reports it idles funny, sounds like he's got the intake leak to me. I'll run away from this one. I really appreciate your thoughts and input on this one. 

 

I've located a much, much, closer 252H with a Kaw under the hood. No plow. I have one and a snow thrower. I have no need for another tractor. That is no reason not to get one  Trying to contact the fella and see if he haggles. If it seems promising I'll start a new thread if I can't search up the good stuff on this mill.  If this one doesn't pan out, I could run across another Onan twin and will know of the features you mentioned to look out for. So your words are not wasted and likely will help another, future jockey.  

[Achto 29,310]

43 minutes ago, Jon Paulsen said:

I've located a much, much, closer 252H with a Kaw under the hood

 

Just a note: The 252H is a vertical shaft lawn mower, not a garden tractor.

[Jon Paulsen 291]

1 hour ago, Achto said:

 

Just a note: The 252H is a vertical shaft lawn mower, not a garden tractor.

Thank you @Achto is the main differatnce that it would be a bit light duty and be challenged with pulling much weight?

 

I have a 95 38XL with a 12.5 HP single. I wouldn't want anything smaller or lighter than that one. 

 

I might go back tp plan A and get a craftsman, then rebuild my opposed twin and replace the water logged engine in the craftsman. I'm just in it for entertainment at this point. If the 252H is light in the saddle and the craftsman/opposed doesn't work out, I can find something else to keep me of the streets. That's a delicate balance. If she thinks I'm enjoying this, it could get kyboshed fast. Yet if I moan and groan too much, I could be told to pay someone to do the work or worse, buy new. 

 

Yes, I wear the pants in this house when SHE's no around 

[Achto 29,310]

2 minutes ago, Jon Paulsen said:

is the main differatnce that it would be a bit light duty and be challenged with pulling much weight?

 

Yes this would be the main difference. The 252H will have a stamped sheet metal body, Peerless tranny, vertical shaft engine. It was made to be a lawn tractor, not a garden tractor.

 

A fast tell to I.D. a  as a garden tractor would be a horizontal shaft engine and lug bolts holding the rear wheels on. There were some 's that fit this category that had cheap transmissions in them but not too many. If in doubt just give us a shout.

[Jon Paulsen 291]

Thank you so much for that information. I'll move on to another victim. I'm looking for something stronger to play with.

 

OM does say it can amputate hands and feet, so I assume it is at least as strong as a manchette. I'm moving onto something bigger and better or go get that craftsman. I don't know what transaxle it has, but it's a big square aluminum block. So it's likely stronger than the peerless 915 in my XL. 

[lynnmor 7,730]

31 minutes ago, Jon Paulsen said:

 I don't know what transaxle it has, but it's a big square aluminum block.

 

Bzzzzztttt!! right there is where you move on to cast iron.

 

Any of the 300, 400 and 500 series Wheel Horses is where you want to be.  If you look under the rear and see an oil filter on the left side, that will get you a tough hydro-static drive, if you want to use a rototiller a stick shift would do better with that.  You only need high horsepower for serious snow blowing and high grass with a large deck.

 

Did you notice that I have four 520-H tractors?  I also have two spare Onan engines, one of them new, no they are not for sale.  In 32 years the only issues that I ever had with these is one ignition module and a flyball spacer.  The one engine that I bought for a spare was abused and had a mud wasp nest that overheated the rear cylinder causing a loose valve seat which I replaced before using the engine.

[Jon Paulsen 291]

Thanks for the tips @lynnmor !!! 

Now if I don't follow your advice, please take no offence. Your words are greatly appreciated and hopefully I will put them to use in the future. My goal is to give me a meaningless task that I can make sound important. The craftsman I think I can get almost for free. The old B&S twin is just sitting, waiting for employment. If it's not very, very inexpensive I won't be going that route. In fact, I might end up just rebuilding the old twin without it having any employment prospects. I can't remember now, but I think I have about $20 in the twin. I'll probably get a gasket kit for it and maybe rings, depending on what's inside. I'm thinking I'll be in for around 100 diluted greenbacks, unless I get fancy with paint or something  Oh, I can claim I need a spare mower, so I don't go to jail for tall grass. City slicker, me! 

 

Now if all this hoopla gives me as much pleasure as I expect I will, it would be time to move onto something with a CI gearbox, hoy?  I really do appreciate the tips you have given freely. 

 

Please keep this between you 'an me 'an the Internet. I don't want her to beat me again. 

[lynnmor 7,730]

Problem is that you came to a Wheel Horse forum and all of the folks here know that disposable big box store “tractors” are something to be avoided.  Good Luck.

[Jon Paulsen 291]

It's no problem, and I really do appreciate your great advice. Eyeballing a 312-8 less engine. The ad is unclear if it includes a gear box. If she comes with the original gearbox, that might be my lady. That would be better to start out with a better chassis. If it's half the fun I expect, I can continue with improvements. I've decided against the cheaper ones. If I start out with a better chassis, I can go on to conquer the world if I decide to keep moving forward. If not, it seems I could sell and get money back out of it. 

 

312-8 is further than desired, but I'll trailer up and go if I get good vibes about it. The other option might be to go to the tractor salvage yard, but that's even further down the road. The spirit is willing, but I've got some worn out parts in me, and can't find good used replacements. 

[lynnmor 7,730]

Take your time, there are good ones out there.  Be cautious with buying something that was outdoors for years, corrosion is the hardest thing to deal with.  There are members here that can help you with most parts.

[Jon Paulsen 291]

Thank you again. I'm seeing some that were stored outdoors for years. I'll avoid those. I tend to avoid rust, but good to have that reinforced in my tiny brain. 

 

I see a 252H close by, very close. I take it the hydraulic gear box should be avoided. 

 

It seems for every hour I look away from here, I get about $100 less on asking price. No fair!

[lynnmor 7,730]

15 minutes ago, Jon Paulsen said:

Thank you again. I'm seeing some that were stored outdoors for years. I'll avoid those. I tend to avoid rust, but good to have that reinforced in my tiny brain. 

 

I see a 252H close by, very close. I take it the hydraulic gear box should be avoided. 

 

It seems for every hour I look away from here, I get about $100 less on asking price. No fair!

Maybe you missed the 300. 400 or 500 series being what you want.  The 200 series is little more than a box store throw-away and will bring little when you want to sell.  As you are seeing, no knowledgeable buyer wants the silly thing.

[Jon Paulsen 291]

I do appreciate the clarification. I'll narrow the search to the 300, 400 and 500 series then. I was looking everything even close to "in range" (mileage). I'll stop wasting my time on those ads. I didn't know if there were some others with a good CI gearbox. It's a shame so many got "Toro'd." 

 

Thanks again! I do appreciate your tips. I have no experience in any of this. I work on things for fun. 

Edited June 23, 2023 by Jon Paulsen

[lynnmor 7,730]

12 minutes ago, Jon Paulsen said:

I do appreciate the clarification. I'll narrow the search to the 300, 400 and 500 series then. I was looking everything even close to "in range" (mileage). I'll stop wasting my time on those ads. I didn't know if there were some others with a good CI gearbox. It's a shame so many got "Toro'd." 

 

Thanks again! I do appreciate your tips. I have no experience in any of this. I work on things for fun. 

Toro bought the Wheel Horse line and did not do anything bad to them.  if you stick to the 300, 400 & 500 series, the Toro sticker means nothing so long as it says Wheel Horse as well.  I don't know why you are so averse to traveling, sometimes ya gotta do what you gotta do.  I have traveled 400 miles one way to get what I wanted.  If you are wondering why there aren't other members on here, they are at the  big show in PA, some travel considerable miles to attend and some may have driven past your house.  I have several personal reasons for not attending this year.

 

Show travelers

[Achto 29,310]

The 300,400,or 500 series are a great choice. Don't be afraid to go older either. C-series tractors are great workers. Even older name or number series  tractors are great as well. If you want a worker I suggest any Wheel Horse with a big block (10hp to 16hp) single cylinder Kohler engine. Hydro or gear jammer transmission, your choice. Strait up, tractors in this category are easy to maintain & almost bullet proof. 

 

I suggest that you stay away from any Wheel Horse with a 17hp or 19hp twin cylinder Kohler engines. These engines in a Series 1 were prone to issues. The Series 2 engines were much better but not as common in a 

Edited June 23, 2023 by Achto

[Jon Paulsen 291]

Thanks @Achto I was wondering about some of the older ones I've seen for sale. The ones I've seen so far are either very rough or ready for a show. I'd kind of like something in between. Older would be more fun for me. 

 

@lynnmor I have health problems that cause days of pain if I travel very far. I also have serious hearing loss with tinnitus, nerve damage and cancer from chemical exposure (my doctor's opinion on the cancer, not my own). Thank you for explaining how much of a sissy I am. Please stop helping me now. Have a nice day.