Well my 1983 JD 420 garden tractor with the Onan 20 hp finally gave up. the timing set failed, no run. the dilemma is, you cant get Onan parts anymore, so do I try to fix it and get a few years out of it??? or put a Honda gx series on it??? the tractor is in overall good shape but I hate to put 2000 into new power and have the hydro fail. oh what to do....... I am leaning towards repairing it and see how long it runs after that, doesn't owe me anything about 3000 hours on it. 32 years old now. thoughts?? anyone done this??
There are lots of old Onan engines sitting around in dealer's back rooms, so you should be able to find the parts to fix it. I'm sure you have discovered this, but Linamar (Canada) built the Onan engines for years and you may be able to search that way.
http://onanparts.com/index.php?main_page=index&cPath=1_16 I saw this site, hopefully it has parts you need.
I'd fix it. Buy a parts machine and have at it. Sell off what extra parts you don't need if you want. People pay good $ for parts on ebay. Especially the hard to find stuff.
Check out mytractorforum. I'm sure there's some JD forums as well where somebody has run into the same issue, or you may be able to pick up a used engine on the Classified sections there. I think it's probably worth fixing though, you can't beat those older garden tractors!
The problem is that the JD420 is not like the 318 where they sold thousands of them and there are a bunch of them rusting in tool sheds across the country. I don't know if the timing set on the 420 is common to any of the other Onan power plants that were more commonly used but it's worth checking out. I would only consider a major repair of an Onan engine under special circumstances. The first, if you want to repair it as inexpensively as possible and sell the machine afterwards. The second would be if you wanted to restore the tractor to new condition with the factory correct powertrain. As far as useful life of the machine is concerned, only you know how it's been used. If you have worked the trans hard over those 3000 hours, then you have every right to be skeptical. If it's just been cutting grass and pushing snow, then it's got plenty of life left in it. If you have a bunch of attachments for this tractor then you have two great options IMO. Re-power and enjoy it another 20 years, or sell it AS IS and upgrade to something newer. The 4x5 and X4/5/700 series machines are equivalent capacity or you could look for a sub-CUT like the 2210,2305, or 102x machines. 400 series attachments will sell for good $$ to help you upgrade for sure.
This guy isn't far from OH and has parts, motors, etc. http://indianapolis.craigslist.org/grd/5021404779.html
nice, the only problem is none of the original sheet metal fit back on it when it was done. want to stay as original looking as possible. I did consider a 3cyl Kubota diesel transplant, I have a power unit from a generator. but there would be no pto for the mower.
what you have stated is my dilemma, a few attachments, not looking to spend a bunch as I mow with a ZT and plow with a Kubota. Definitely not buying a newer one for what they sell for hopefully tonite when I get it opened up it will be something minor. the engine version I have has a key from the timing gear to the cam, hopefully it sheared.....did not make any unusual noise, just turned of as if you turned the key off. I have limited to the camshaft not turning, took off the manifold and can turn the crank without the cam turning. So I figure a broken gear, but it is to quiet, or the key, tonite will tell. I have found a shop in Ohio that has rebuilt long blocks, might consider that, it will still be original that way.
well looks like its not going to be to bad, sheared a few teeth off the gear. I removed the cam and will replace the bearings while I have it open along with a valve job being it is all apart now. oh and a crank gear, couple of mashed teeth from debris. everything looks new barely any wear lines, wonder why it happened?
well at this point I might as well bore it and add pistons, then it will be rebuilt right. Will have all the gaskets, already disassembled, couple hundred bucks, might as well. 3000 hours I guess she deserves a proper rebuild, about 500 in parts and machine work, last another 30 years???
well things are looking up. I called a guy who has a rebuilt 18hp Onan, direct swap wants 1150 for it. get to talking and he says I got just what you need, I pulled this Onan 20 hp from a JD 420 tractor for a project I never got too. He says I think it has 300 hours on it. walk to the back of the shop, tucked away on the bottom shelf is the engine, he brushes of the dust and sure enough the tag says 300 hours. So I ask how much?? he says give me 150 and its yours. Carb to starter, 4 bolts to attach to frame, 4 bolts to drive shaft, plug in a couple wires done.......luckily I had cash in my wallet, it is now in the trunk of my car waiting to be installed tonite, might be running by morning.
I decided to do all the gaskets and seals while it was out of the tractor, had some seepage and has been on the shelf a while. Cheap insurance, parts should be here Monday. Have it disassembled and cleaned ready to be put back together.
well she lives again...... inspected, cleaned, new gaskets and seals. valve adjustment, carb adjustment, runs like new. amazing how much down on power it was, never noticed it. 32 more years.... $350 total invested
