That's what i thought. I drained a little then started the tractor and ran a little fwd and rwd. then checked again. It looks a little low now so I will slowly top up. I guess the OM should say put in 3 qts. then start checking. I discovered I had already put in 3 to 4 Qts based on what was left in the jug. I think I have it now. Whew.

Put a straw down next to funnel to burp air. If you changed the filter loosen it a couple turns that helps also. Don't forget to tighten after. Odd that it comes out the bolt hole. Sounds like you maybe trying to over fill it. Oil should never reach the level of that bolt.

Hello. I just drained the oil out of my 1988 520H with the hydrostatic transmission. Upon trying to put oil back in I came upon a problem. Only a small amount of oil went in then it stopped and now it just overflows if I try to put any more in. The owners manual just says "After adding 4 quarts of oil..." Well I never got 2 quarts into it. What am I doing wrong? Any little trick I need to know? On my older C120 it says to remove one of the top bolts but if I try that on my 520H it just leaks all the oil out the bolt hole.

I just got a 1993 with all attachments , snow plow,grass catcher..... $400. 356 hours on meter hope that is a good price?

Oil attracts dust grass chaffe, over time it causes more wear and it gets to sticking instead of smooth flowing motion control movements again my experiences but I prefer the graphite powder and I'm pretty sure is says NOT to in the OM.

You can lube anything on or near the hydro except the friction washers on the cam plate. Of course lubing the cam groove might cause lubricant to migrate to the friction washers if too much is used.

@WVHillbilly520H thanks for the warning about not lubricating the hydro cam/ eccentric with oil. I luckily have not lubed that for whatever reason. I have only been doing linkages and where shafts pass through a hole or bushing type things... But can you tell me why you would use only dry graphite powder... I was guessing maybe oil would cause it not to " return to" or "rest" in neutral...

@WVHillbilly520H thanks a million for your input and opinion. And @lynnmor. Having you fellows input really steers me in the right direction. I agree with you Jeff when you say if it ain't broke don't fix it, but like another horseman mentioned, now would be a good time to adjust the lifters since I had it tore down this far. I really don't know the history of the tractor and with all the other stuff I have done: 1. Clean debri from engine tins. 2. New spark plugs. 3. New Coil 4.Check wiring and clean and grease all terminals. 5. New Battery. 6. New Oil pressure switch 7. Wired oil pressure switch to properly work hour meter. 8. New hour meter. 9. Change engine oil and filter 10. Change hydro oil and filter. 11. Rewire 30 amp charger circuit wire bypassing 9 pin connector that was burnt. 12. Rewire 20 amp starter circuit wire bypassing 9 pin connector that was burnt.(I now have a 7 pin connector...lol) 13. New fuel pet cock and bushing. 14. New fuel line 15. New fuel pump. 16. New nylon bushings on hydro lift and direction control levers. 17. New Air seal gasket/ grommet around oil filter. 18. New dash bulbs. 19. New(to me) air tube from engine housing to air cleaner box. 20. Re pipe loose oil drain pipe on engine. 21. Sand blast, weld crack in muffler. 22. Repaint muffler. 23. Repaint muffler heat shield. 24. New rear tire. 25. New carb. 26. New battery box. 27. New battery hold down. 28. Replaced missing plastic flywheel shroud/ guard. 29. Cleaned and resealed intake manifold. 30. Lube all grease fittings. 31. Oil all pivot points with "3 in 1" machine oil. I figured go ahead and check/ adjust the lifters... Hopefully with doing these things I will have caught it back up on some of its needed maintenance and possibly ensured a few good years of use. Of course after I get the 520H right, then I start on the 48 inch side discharge deck, Then the 36 inch rototiller...

Please DON'T oil the hydro cam/eccentric the only lube to use on this (not just my opinion) is a dry graphite power... And whether or not you have seen my used 520H thread here's what I started with and it only had 236 hours on a working meter... I hope these help you as you go along as well... Good luck.

@WVHillbilly520H thanks a million for your input and opinion. And @lynnmor. Having you fellows input really steers me on the right direction. I agree with you Jeff when you say if it ain't broke don't fix it, but like another horseman mentioned, now would be a good time to adjust the lifters since I had it tore down this far. I really don't know the history of the tractor and with all the other stuff I have done: 1. Clean debri from engine tins. 2. New spark plugs. 3. New Coil 4.Check wiring and clean and grease all terminals. 5. New Battery. 6. New Oil pressure switch 7. Wired oil pressure switch to properly work hour meter. 8. New hour meter. 9. Change engine oil and filter 10. Change hydro oil and filter. 11. Rewire 30 amp charger circuit wire bypassing 9 pin connector that was burnt. 12. Rewire 20 amp starter circuit wire bypassing 9 pin connector that was burnt.(I now have a 7 pin connector...lol) 13. New fuel pet cock. 14. New fuel line 15. New fuel pump. 16. New nylon bushings on hydro lift and direction control levers. 17. New Air seal gasket/ grommet around oil filter. 18. New dash bulbs. 19. New(to me) air tube from engine housing to air cleaner box. 20. Re pipe loose oil drain pipe on engine. 21. Sand blast, weld crack in muffler. 22. Repaint muffler. 23. Repaint muffler heat shield. 24. New rear tire. 25. New carb. 26. New battery box. 27. New battery hold down. 28. Replaced missing plastic flywheel shroud/ guard. 29. Cleaned and resealed intake manifold. 30. Lube all grease fittings. 31. Oil all pivot points with "3 in 1" machine oil. I figured go ahead and check/ adjust the lifters... Hopefully with doing these thing I will have caught it back up on some of its needed maintenance and possibly ensured a few good years of use. Of course after I get the 520H right, then I start on the 58 inch side discharge deck, Then the 36 inch rototiller...

That's the lifters that are loose but yes that's how I adjust them on the Kohlers, I suppose someday I should adjust the lash on my 520s, (if ain't broken i ain't fixed it yet) but even on my solid lifter SBC I would rotate the engine over until the pressure is completely off the rocker before adjustment.

I'll try to repost the video. @lynnmor 20201118_205102.mp4

@lynnmor Thank you for all your help !

Reread my instructions on adjusting the valves: "So you don't have to look for timing marks and still not have the cam in the best position, there is a simple way to get in the position to adjust a valve. Choose a valve and rotate the engine to where the valve spring is compressed to the maximum amount, now mark the pulley with chalk and rotate the engine one full turn. Adjust that valve and repeat till all four are done. Use the next size smaller and larger feeler gauges as go and no go gauges to be sure that you have it right. If you find valves that are more than a few thousandths off specification, stop and report your findings." Your last video will not play on my system. If you didn't split the intake halves, the sealant on the outside will do nothing. There are instructions at the top of the engines section describing one way to reseal an intake. I don't tap the one half, I just use screws, washers and locknuts. That groove in your photo is exactly what I was talking about, I believe that nearly all have that same issue.

20201118_205102.mp4 20201118_205102.mp4 20201118_205102.mp4 20201118_205102.mp4 @lynnmor I closely inspected the intake manifold and DID find where the heat shield was rubbing it. Cleaned it up and resealed where the two halves meet. (see pics) Also rotated my engine untill both vales were loose on the # 1 cylinder... Am I ready to check/ adjust valves? (see video 20201118_205102.mp4 20201118_205102.mp4 20201118_205102.mp4 )

I'm not a fan of the cheap Chinese carburetors, some have good luck, others not so much. "Rebuilding" a carburetor, that doesn't have excessive wear, simply means doing a meticulous cleaning. Anyway, check that there are no leaks between the intake manifold halves and check if the heat shields cut into the side of it. Cut a bit off the heat shields if they touch. Use genuine Onan intake manifold gaskets, cheap Chinese gaskets will fail. So you don't have to look for timing marks and still not have the cam in the best position, there is a simple way to get in the position to adjust a valve. Choose a valve and rotate the engine to where the valve spring is compressed to the maximum amount, now mark the pulley with chalk and rotate the engine one full turn. Adjust that valve and repeat till all four are done. Use the next size smaller and larger feeler gauges as go and no go gauges to be sure that you have it right. If you find valves that are more than a few thousandths off specification, stop and report your findings. Back to the dirty carburetor, The white plastic limiter cap can be pried off and the idle mixture screw will then come out. That "drain plug" is just an access port to switch the main jet for different elevations. The welch plug just above the idle mixture screw should be removed for cleaning, especially on a carburetor this dirty. If you have success with the cheap carburetor, I would be interested in the old one. The white on the exhaust valve is the result of too little fuel getting thru the dirty carburetor, that isn't a problem unless the engine was run hard while running lean. Many point to the valve seat issues in Onan engines, but any engine with removable valve seats can suffer damage from the abuse of running too lean. Keep fresh fuel in your equipment and don't store it long term with ethanol fuel in the carburetor, run it dry for storage and any fuel can be used. Even stored gas in cans should not be kept long term and keep the cans tightly closed except for quickly filling your equipment. You can use the 10% ethanol fuel to save money, but follow the rules. Be sure to thank your government leaders for the extra work. With the exhaust painted, valves adjusted, carburetor cleaned, intake manifold inspected and all new gaskets you should be good for years to come. As you are learning, shortcuts, (for example: snake oil) don't pay.

@WVHillbilly520H I ordered the carb in the link above. I believe that will be the best route considering I could order a carb rebuild kit, rebuild carb, and it still not work and have to do it again. I do believe that I will adjust the valves while I have it apart. Thanks for the video !!

I'm leaning towards new carb for $50 or so... Never rebuilt a carb. I use non ethanol fuel in all my equipment( wish the previous owner did. Okay @cleat and @lynnmor jump right in...what' s you fellows vote on the new carb or rebuild... Remember never rebuilt a carb before.

You may be able to "soak" it out in a carb bucket (I prefer Berrymans over Gunk brand) you will definitely want to get a rebuild kit. That build up is from ethanol laced fuel, those parts you are pointing at with the ink pin are 1) the Welch plug it can come out but you will a new one then reseal when reunstalling 2) the idle limiter cap won't hurt to soak it, there are some new aftermarket carbs on eBay for $40... @lynnmor may be of more help or @cleat, I really haven't had too many issues with my Onans in the past 22 years. https://www.ebay.com/itm/164508116811. https://www.ebay.com/itm/353238601396

Ha !... You beat me to it Jeff...mind reader !...😝

@WVHillbilly520H , @lynnmor , @Achto Okay 520H / Onan P220 veterans... Time to send the city boy to school... Does the two do- hickeys need to come out that the blue pen is pointing to ? Take a look at the pics... the carb looked like a dumpster that had been sitting outside.(was outside when I bought it) Do you think a soaking in Gunk carb cleaner will do it, or do I need to: a. Buy an ultrasonic parts cleaner. b. Buy carb on internet. Also while this topic is all over the place, could one of you describe how to adjust the valves ?... I ended up taking carb and manifold off/ aint no way taking just the top off carb off was gonna do it. Look how corroded the bowl drain plug is. Take a look at those valve stems in the pics and chime in please with your thoughts. Thanks, Tim ah...Horse Newbie

Valve adjustment...

Yes it seems to smooth out when I choke it a bit at idle...guess I'll be pulling the top off the carb at least...

Yeah I was wondering if I should have adjusted the valves...but not being what I would call a mechanic I was afraid I would do something wrong and tear something up. @lynnmor take a look at the video attached and tell me what you think. I could lower the throttle to almost or/at idle and put my finger over the little hole in the carb then it seemed to smooth out some. By the way, I got my hour gauge working by following your directions... The oil pressure switch with the 3 terminals worked... Ran blue wire to indicator light... Black wire to "-" on hour meter... And figured out which terminal to ground to block. Thanks for the help ! If I get the carb issue straightened out, and she runs good I may have to study on adjusting the valves. I know I've gotten off topic. Tim (Horse Newbie) 20201112_183856.mp4 20201112_183953.mp4

If you were to "choke" while idling does the "searching" smooth out? If so like Lynmoor said pull the top and clean as much as you can using spray carb/jet cleaner in every orifice (make sure to shield your eyes) reassemble try again ... May need to do this several times... Not a fan of Seafoam as much i like Berrymans B12 for fuel system cleaning i personally use about 1/4 or can per tank... And actual small engine shop back home swore by Marvel Mystery Oil in the crankcase and fuel tank for Kohlers and my dad used it religiously without much issue.