dkg520 499 #1 Posted June 17, 2018 This weekend after I finished mowing my yard I noticed my 1995 520H that I purchased new rolled over 1000 hours. Besides routine maintenance which includes oil and filters, spark plugs and air filters, belts and a new set of tires it runs like new. Sometimes I think the Onan motors get a bad rap. How many hours on your 520? Share this post Link to post Share on other sites
cleat 4,936 #2 Posted June 17, 2018 I have never had a major failure on any of my Onan's. I currently own 5 520's and have sold a handfull of 416's. Other than carb cleaning on a few, and one ignition module failure on the HC, they have been reliable. I have not gone through the latest 520 yet but it runs smoothly. I can't tell you hours on most as hour meters never seem to work when I get them (But I bet they are high enough due to the wear on other components). The latest one is showing over 3000 but that may not be right. Share this post Link to post Share on other sites
lynnmor 6,762 #3 Posted June 17, 2018 I have approximately 1000 to 1400 hours on each of my three 520's. I have had some valve wear on one valve in one engine that had the compression down to 70 psi, so I did a valve job to freshen it up. Other than that, I lost one coil and needed some carburetor work. You are overdue for a valve adjustment and possibly a de-carbon of the combustion chambers. Carbon buildup can vary considerably by how it was used, gasoline quality and type of oil. Share this post Link to post Share on other sites
dkg520 499 #4 Posted June 17, 2018 I agree with you. I have not done any of that. It always starts and runs so well I hate to mess with it. Share this post Link to post Share on other sites
Kurt-NEPA 755 #5 Posted June 18, 2018 (edited) I have two 520H's. One has 310 hrs. and runs and looks like new, the other has 1165 hrs. and run as good as the other. I sold one a few years ago, it had 2600 hrs on it and the hour meter and it had not worked in years. It was running good, but the valve seats were badly worn. (Yes I told the buyer - I sold it as a roller with parts engine). I've read all the stories of loose valve seats, but my 520H's had been solid performers. I love the sound and performance of these old flat heads. Edited June 18, 2018 by Kurt-NEPA Share this post Link to post Share on other sites
lynnmor 6,762 #6 Posted June 18, 2018 1 hour ago, dkg520 said: I agree with you. I have not done any of that. It always starts and runs so well I hate to mess with it. If a valve wears and you lose the clearance, it can burn both the valve and seat. It is just proper maintenance for any solid lifter engine. Since it is necessary to remove the exhaust and intake to adjust the valves, I glass bead the muffler and paint with high temperature Rust-Oleum, and clean the carb as well. A good muffler is hard to find and can be expensive. 1 Share this post Link to post Share on other sites
