First post. Been lurking for a year.
So I caught the Wheel Horse bug last year when I bought a '90 520H. Had about 950 hours. Came with 42" deck and plow. Guy I bought it from was really decent and said that the rear cylinder was starting to lose compression. When tested it was lower than I liked but not horrible. As I recall right around 100 hot, maybe just below. (Note to self: clean out fins after every use.) The guy also threw in a blown Onan 20 from another 520 swap he had done. I bought this with the full understanding that, sooner or later, I was going to be facing the dilemma I am now facing. Unfortunately, it is sooner.
I ran the tractor all summer, cutting a total of about 2.5 acres of ground every week or so. Was dutiful about clearing fins, but it was pretty dusty a couple times when I cut. Did service the breather once. Fell in love with that machine! Couldn't wait for a snowfall to push it around with the blade. In the mean time the guy I bought from had a 60" deck I had been eyeing when I picked up the tractor, and he offered it to me at a good price. Picked it up, installed it and used it for last cut of the season - a really dusty one, I might add. Ran like a dream! Deck was perfect and cut my time down considerably. I had a little slippage on PTO start up, but once moving, that deck screamed! After that last cut, I parked her in the equipment shed, put some stabilizer in the fuel, patted her nicely on the hood and wished her a good winter until the snows fell.
A few weeks later, I happened to be in the equipment shed and thought I would turn her over just to keep the carb clear. She started, but she was not happy about it. When I pulled her out, it was pretty clear she was only running on one cylinder. After a while I could feel the second one kick in. Hoping against hope, I changed the plugs, thinking one might have gone bad. Nope. So, because I didn't have time that day to fiddle further, I let her sit for a few more weeks. When I came back, I could not get her to start at all, until I took off the breather assembly, and then it was ragged. After a while she would not run at all. Upon inspection I realized that it looked like spurts of fuel were coming out of the top of the carb assembly. Cold compression was 95 on the front cylinder and 5, yes 5, on the back.
OK, so I've now gotten past denial stage and moved on to acceptance. I need to do something. I have lots of options. I am assuming that I have a valve problem on the engine currently in the tractor. May be something else, but, come on, its an Onan PG 220 and these are fairly classic symptoms... I think I just put it over the edge with that big deck. I probably could have babied it for another season with the smaller deck, but I had to save time!!! I don't really know what is wrong with the spare/part engine the guy threw in, but I am assuming the same thing. (Yes, I know what assuming does.)
So here is (are) the question(s): Do I take these Onans to someone (because the guts of an engine, outside of maybe repairing or replacing a carb, are beyond my current skills set) to try to patch together a workable engine from them? Do I just chuck it and do a complete swap with a new engine? (which I feel fairly confident I could accomplish on my own.) And if so what engine? Options - HondaGX690, a Vanguard of similar size, the HF Predator, and maybe a Kohler.
In giving your advice recognize a few things:
1. I HAVE the money to go all out on the replacement, but I am cheap as hell. The predator appeals to the second part of that. Have looked at the thread of the guy who did that replacement, so it looks simple enough, but wonder about the long term durability.
2. Similarly, I can probably afford whatever it would cost to combine engines, but, again, I am cheap as hell. I hate paying someone else to do work for me that I could do myself, or do the substitute of. Also, I worry a bit about the long term logic of fixing a 25 year old engine with another 25 year old engine. At the same time, I really loved the way that Onan roared.
3. I am fairly mechanically capable, but with limited knowledge or tools for progging around in the internal workings of an engine. Hook ups and problem solving for a retrofit should be no problem though.
4. Time is not a huge issue. I currently have a POS mower that does the job, but, sadly, is not a WH. I want to RIDE again, though....
Hit me with your best shot...