Shuboxlover 481 #1 Posted June 28, 2010 on my 520HC..... All fluids are o.k. It looks like there should be some sort of dash plate up there, but it's missing, so I don't know what the light is trying to tell me, but it hasn't flashed like this since I bought it 2.5 months ago. :thumbs: Share this post Link to post Share on other sites
wh500special 2,277 #2 Posted June 28, 2010 That's the oil pressure light. It is supposed to flash if the oil pressure is low. It could be an electrical gremlin giving a false trigger, but you're going to want to verify you have adequate pressure with a gauge before you toast your engine. Steve Share this post Link to post Share on other sites
Nick 13 #3 Posted June 28, 2010 Does the light continue to flash when the tractor is running? If i remember right the oil pressure light flashes until the engine starts. Share this post Link to post Share on other sites
pfrederi 18,690 #4 Posted June 28, 2010 The light should flash whenever the ignition is on. Once it senses oil pressure (about 5 lbs I think) it should turn off. The sending units are available from Toro Stens and others (used by JD and others) and not expensive. As indicated above could be a gremlin or bad sender, but you want to check it out before you run it and ruin the motor Share this post Link to post Share on other sites
Shuboxlover 481 #5 Posted June 28, 2010 How do I check it? Share this post Link to post Share on other sites
pfrederi 18,690 #6 Posted June 28, 2010 unhook the wire from the sending unit. Check for continuity between the sending unit terminal and the engine block. The start the engine and test for continuity again. Should be different readings one an open circuit and one a very low resistance. If not get a new sending unit.. Share this post Link to post Share on other sites
Shuboxlover 481 #7 Posted June 28, 2010 unhook the wire from the sending unit. Check for continuity between the sending unit terminal and the engine block. The start the engine and test for continuity again. Should be different readings one an open circuit and one a very low resistance. If not get a new sending unit.. Thanks...easy enough..... how do I check oil pressure? Share this post Link to post Share on other sites
Shuboxlover 481 #8 Posted June 28, 2010 Oh....and where is the sending unit? Share this post Link to post Share on other sites
pfrederi 18,690 #9 Posted June 28, 2010 You will need a gauge to check the pressure. That is why I would check out the sending unit first. If it works and the light still flashes it could be an issue with the circuit board the light is on or it could be you really have no pressure. Do you have a pressure testing gauge??? If not buy a SunPro mechanical oil pressure gauge and hook it up. You can always use it later on your D-160 to replace the non working/leaking electrical unit. Share this post Link to post Share on other sites
Shuboxlover 481 #10 Posted June 28, 2010 Where do I hook the gauge up at?......sorry, new to this whole pressure testing thing :thumbs: Share this post Link to post Share on other sites
pfrederi 18,690 #11 Posted June 28, 2010 remove your pressure switch and thread the pressure gage tubing into that hole....The sunpro 2" gauges come with several threaded adapters that have fit everything I have used them on (Wheel Horses, and old farm tractors even an Mil vehicle)...I do not have any Onan's You do not need to mount the gauge for the test Share this post Link to post Share on other sites
Fiddlestix 0 #12 Posted June 28, 2010 I do not know if the HC has an hour meter but if you do and it functions, check to see if it still functions when the engine is running (while checking pressure). I believe at low pressure condition, the pressure switch closes to energize warning light and opens the hour meter. This is so that if the key were left on after shut down, the hour meter does not wind up excess hours. It comes on line when pressure is present. If the hour meter still functions, there are likely electrical issues outside the engine. By all means verify with a pressure gage. But the hour meter check can help reassure and pinpoint things. Share this post Link to post Share on other sites
bowtieguy 334 #13 Posted June 29, 2010 I bought a 417-A at an auction but never noticed that the wire going to the pressure sending unit was UNPLUGGED until I got it home....hooked it up and the red light started blinking while engine was running...(so I figured I bought a junker engine that needed internal work) but I thought I might as well replace the unit to see if it was the problem....bought a new one from Kohler....as I took the old one out of the engine I noticed it was a bit "different"....found out that someone had replaced it at one time with a automotive unit (guess that is the reason they left the wire unhooked)...put the new Kohler unit on and everything works fine...light blinks until engine starts then goes off. I think the 17 hp Kohler Series II engine carries about 30+ oil pressure.....you might want to verify that you have the correct sending unit on your engine :thumbs: Share this post Link to post Share on other sites
Shuboxlover 481 #14 Posted July 1, 2010 Where is the oil pressure sensor located on the 20HP Onan? Share this post Link to post Share on other sites
