IanT720 2 #1 Posted November 24, 2017 Hopefully this is an easy one for the fellas and ladies on here... bought a 520H with the 20hp ONAN... checked the oil when I got home. It was like water... smelled of fuel. It had been sitting for a year at this point. So I changed the oil, ran it. Seemed fine.. started it a week later... Oil was iffy... so I ordered a new float and float valve. It’s the usual culprit. And changed the oil again. Used it all summer seemed great. Now I haven’t ran it in a solid month or two.. and checked the oil and it’s all thin and smells of gas again! So... I noticed it was stored with the fuel valve on the bottom of the tank open. Should it of been closed? Is this why? Getting sick of changing the oil... Share this post Link to post Share on other sites
ol550 825 #2 Posted November 24, 2017 Would invest in a fuel pump. Vacuum operated, most likely a bad diaphram. About $30 on $bay. 3 1 Share this post Link to post Share on other sites
Spareparts 84 #3 Posted November 24, 2017 I don't mess with the tank vale anymore, most of the time they don't shut the fuel off all the way and most of the time leak if disturbed. I go to TSCand get a inline 1/4 turn valve and install in line, and as suggesten the fuel pump could be bypassing fuel. 2 Share this post Link to post Share on other sites
cleat 4,936 #4 Posted November 24, 2017 I second the fuel pump. A hole in the diaphragm would pass fuel directly into the crankcase. Since the carb on a 520 is much higher than the tank, I would not think that a bad float would cause your problem. Cleat 1 1 Share this post Link to post Share on other sites
SylvanLakeWH 24,088 #5 Posted November 24, 2017 And Good to see another Michigander!!! Grew up in Ann Arbor but we did our skiing and tubing on Whitmore Lake!!! Share this post Link to post Share on other sites
953 nut 51,511 #6 Posted November 24, 2017 Reading your post the vacuum fuel pump came to my mind also, I am an advocate of installing electric fuel pumps if the factory pump has a problem. 1 Share this post Link to post Share on other sites
IanT720 2 #7 Posted November 24, 2017 Would of never guessed the fuel pump! I will investigate! Thanks for the tips!!! 2 Share this post Link to post Share on other sites
