Ed Kennell 37,481 #1 Posted March 8, 2014 Picked up this beast this morning. Has a good deck, but I plan on putting my spare blower on and make it my primary snow mover. I'll put the Tecky powered C-120 into semiretirement.... It has had a long working life and deserves a little R&R. Can't wait to try that hydro lift. 5 Share this post Link to post Share on other sites
Tankman 3,516 #2 Posted March 8, 2014 Nice find! The lift should be excellent for the blower. By all means, post updates! 1 Share this post Link to post Share on other sites
Sparky-(Admin) 21,075 #3 Posted March 8, 2014 I'm sure your going to go thru it, fluids, filters, grease etc....but since its new to you I would take the time to get the engine tins off and make sure its clean of any build up such as grass clipping. Overheating is bad for the ONANS. Nice find, should prove to be a great worker! Mike............. 2 Share this post Link to post Share on other sites
squonk 40,739 #4 Posted March 8, 2014 Hydro lifts ARE THE BOMB!!!!!!! 3 Share this post Link to post Share on other sites
varosd 1,185 #5 Posted March 8, 2014 looks like she will clean up real nice. How many Hours? the light buckets are still available. 1 Share this post Link to post Share on other sites
JERSEYHAWG / Glenn 4,497 #6 Posted March 8, 2014 Very nice & good luck. Glenn 1 Share this post Link to post Share on other sites
Fun Engineer 859 #7 Posted March 8, 2014 (edited) Hydro lifts ARE THE BOMB!!!!!!! Absolutely agree. Edited March 8, 2014 by Fun Engineer Share this post Link to post Share on other sites
leeave96 487 #8 Posted March 8, 2014 Very nice find. You will be amazed at that tractor with Matt's foot control kit if add it. 1 Share this post Link to post Share on other sites
Ed Kennell 37,481 #9 Posted March 8, 2014 Thanks for all the tips. I'm sure I will need your advice and help as I get into this tractor. Just when I have the Kohlers pretty well figured out, I bring an Onan home . After checking the fluids and charging the battery, I was able to get her started this afternoon. She has some wiring issues...Had to run 12V to the solenoid with my switched jumper wire. She has a lot more wiring, fuses and safety switches than the Cs that I am used to working on. I need to print the wiring diagrams to see what all is not working. She sounded good with no smoke and ran good at full throttle, but at low throttle, she keeps surging and searching for RPM. I had go to 1/2 choke to stop the low speed surge. Carb. and gov. work coming. I did give the hydro a quick test... Pulled the front wheels up against the big truck tire on my wood hauling trailer and she can spin the wheels on the blacktop. All advice is appreciated... I am a NEWBIE on the Onan. Share this post Link to post Share on other sites
KC9KAS 4,741 #10 Posted March 8, 2014 Nice find ...That 520 looks like it will be a snow-blowing machine! Share this post Link to post Share on other sites
ericj 1,578 #11 Posted March 9, 2014 if you need help i'm just up the road from you. nice score, i just drug home a 518 today it started and ran but needs a lot of tlc will probably part out eric j 1 Share this post Link to post Share on other sites
cruisnblue48 835 #12 Posted March 9, 2014 Nice find, Ed! 1 Share this post Link to post Share on other sites
Ed Kennell 37,481 #13 Posted March 14, 2014 I'm sure your going to go thru it, fluids, filters, grease etc....but since its new to you I would take the time to get the engine tins off and make sure its clean of any build up such as grass clipping. Overheating is bad for the ONANS. Nice find, should prove to be a great worker! Mike............. Took your advice Mike. Whata mess I found. PO must have been a grease nut. A lot more junk under the hood than the Cs with the K engines. A couple pounds here And here Looking better Share this post Link to post Share on other sites
Wheel-N-It 2,968 #14 Posted March 15, 2014 Well the good side of that is the PO didn't let any moving parts run dry. Even the inside of the wheels 2 Share this post Link to post Share on other sites
boovuc 1,090 #15 Posted March 15, 2014 While you have it apart.......better adjust the valves on it! Now is the perfect time to do it with everything opened up! If your in a particularly jaunty mood...take the heads off and de-carbon the tops of each cylinder. You'll need to order a gasket set to do it but it is worth it in the long run. Again, since you have it torn down this far and time before snows and grass growing to do it! 1 Share this post Link to post Share on other sites
GMan 82 #16 Posted March 15, 2014 Ed, Be sure to replace the gasket under the oil filter mount. Onans are famous for coming loose with time and that is the only thing I know of on them that wouls allow that much oil to leak out. You can see that it is around the cut-out area for the filter. Onan has improved the gaskets for that position too. Also it wouldn't hurt to Loctite the bolts when you re-install them....................Gary 1 Share this post Link to post Share on other sites
Ed Kennell 37,481 #17 Posted March 15, 2014 While you have it apart.......better adjust the valves on it! Now is the perfect time to do it with everything opened up! If your in a particularly jaunty mood...take the heads off and de-carbon the tops of each cylinder. You'll need to order a gasket set to do it but it is worth it in the long run. Again, since you have it torn down this far and time before snows and grass growing to do it! Will do Boo...What do you set your valves at ? Ed, Be sure to replace the gasket under the oil filter mount. Onans are famous for coming loose with time and that is the only thing I know of on them that wouls allow that much oil to leak out. You can see that it is around the cut-out area for the filter. Onan has improved the gaskets for that position too. Also it wouldn't hurt to Loctite the bolts when you re-install them....................Gary So that's where all that oil came from... Thanks Gary Share this post Link to post Share on other sites
GMan 82 #18 Posted March 16, 2014 Ed, I know you directed your question to Boo, but I looked in my manual to find the intakes are supposed to be at .005 and the exhaust at .013. Be sure you have the pistons at TDC on the compression stroke (valves completely closed) when you set them..................Gary 1 Share this post Link to post Share on other sites
Ed Kennell 37,481 #19 Posted March 16, 2014 Gary.....all help is appreciated. Share this post Link to post Share on other sites
Martin 2,131 #20 Posted March 16, 2014 Ed, like has been mentioned before, take care of the valves and decarbon while its apart. the intake has to come off to do the valve clearances. bit of a pain, but these engines are worth looking after. a little maintenance goes a long way and who doesn't like caring for our wheel horses? Before the Onans started appearing in my garage i didn't have much good to say about them, ignorant i guess, i thought nothing could draw my attention away from the simplicity of the k series Kohlers. Well times have changed, and while the Kohlers still impress me with their simple, uncomplicated makeup, the Onan has impressed me with how well made an engine they really are. they are a bit of a pain to work on, spare parts are more expensive, but there is something about them that has got me hooked on them...... 3 Share this post Link to post Share on other sites
JackC 617 #21 Posted March 16, 2014 Surging? Be sure to clean the carburetor. 1 Share this post Link to post Share on other sites
boovuc 1,090 #22 Posted March 16, 2014 Thanks for answering him, Gary! 1 Share this post Link to post Share on other sites
GMan 82 #23 Posted March 16, 2014 Ed, In re-reading your original post I noticed you had mentioned "surging" at lower RPM and felt led to respond further. I have had considerable experience with these Onan engines and have found surging to be created by one of or a combo of three things. Onan carbs have a small expansion plug on the face side (same side as adjustment screw) that has tendancy to loosen up or worse to come clear out, and although this can happen it generally creates extreme surging. Second, is as mentioned in an earlier response a dirty carb. This can generally be taken care of by removing the top of the carb and servicing it from there. One particulaer area to look for in doing this is to remove the Idle Jet that is screwed into the lower body and be sure all of the side holes and the bottom hole in it are clear. I use a set of gas welding tip cleaning wires to do this task. Third and lastly, the carb manifolds are cast in two (2) pieces and glued together with a sealant from the factory. With age and continual heating up of the engine this sealant deteriorates resulting in the manifold sucking air. Since you are taking this manifold off anyway to adjust the valves I would pry the manifold apart and reseal it. This isn't that hard to do. One half of the manifold has guide pins cast into it and if you are careful these can be maintained. However I have had them break off separating the two halves. This isn't a big deal as they can be drilled out and replaced by some small #10-24 screws and nuts. Carefully clean the old gasket material off, trying to be very careful not to mar the gasket sealing surface. After cleaning it and washing it down with brake cleaner, laquer thinner or some similar type cleaning agent, apply an ample but conservative application of "Permatex MotoSeal 1 Ultimate Gasket Maker Gray" . This material is impervious to gasolene and ethonal infested gasolene and will hold up. You can use bolts through the end holes used to mount the manifold to hold location and to aid in clamping until the new sealant dries. Let it dry 24 hours before the manifold is bolted back into place.......................Hope all this helps in youe endeavors......................Gary 4 Share this post Link to post Share on other sites
GMan 82 #24 Posted March 16, 2014 Boo, You are welcome.............Just trying to be of help as I too love these Onans and try my best to keep them alive. No engine sounds like them with that "throaty" growl they have while under load and I love that sound at idle...............Gary 1 Share this post Link to post Share on other sites
Ed Kennell 37,481 #25 Posted March 16, 2014 To all for the interest in this project. The "TO DO LIST" is really growing and I will try to do it all, but It may take awhile as the warmer weather here has me thinking about getting the boats ready to move to Delaware. A couple new questions did come up. Thinking about ways to keep the back cylinder cooler, I do plan to add vent holes to the belt guard, and am thinking the tin shield covering the exhaust pipes and muffler must restrict the amount of air across the cylinders. Has anyone tried removing that tin or parts of it with any positive results on cylinder cooling ? Is the purpose of that tin to cool the exhaust pipes and muffler or to contain that heat and keep carb. cooler ? The other concern is the steering.... the wheel has ~2.5" of slop measured at the wheel OD. I'm sure this excessive, but what is normal, and what is best way to fix It ? I have not taken the battery and tray out yet to see what is and isn't moving when turning the wheel. The wheel is also ~90 deg out of position when the wheels are straight. If the steering gear jumped one tooth in the sector, would that equal 90 deg of wheel movement ? again for all the help. Share this post Link to post Share on other sites
