formariz 11,849 #1 Posted November 28, 2018 On my 520H I have this brass fitting in the air cleaner.It has a barbed end on the other side. Saw it in service manual with a small hose attached to it, but it does not tell me what to attach it to. I cant see where to connect it to. Share this post Link to post Share on other sites
benji756 341 #2 Posted November 28, 2018 (edited) I think it goes to the air filter for some kind of sensor Edited November 28, 2018 by benji756 Share this post Link to post Share on other sites
Pullstart 58,777 #3 Posted November 29, 2018 Baahhhh!!!!! Emissions on a Wheelhorse.?? 2 Share this post Link to post Share on other sites
lynnmor 6,698 #4 Posted November 29, 2018 A 5/32" vacuum hose is connected to a switch mounted behind the instrument panel next to the battery. When the air filter becomes restricted with dirt, the vacuum increases and the switch turns the warning light on. Often the switch has the hose connection broken off. Restore the system or cap the fitting to prevent dirt from being drawn inside. Switches are available here, currently the website is being updated. I have repaired switches with a custom made aluminum adapter. 4 2 1 Share this post Link to post Share on other sites
formariz 11,849 #5 Posted November 29, 2018 34 minutes ago, lynnmor said: A 5/32" vacuum hose is connected to a switch mounted behind the instrument panel next to the battery. When the air filter becomes restricted with dirt, the vacuum increases and the switch turns the warning light on. Often the switch has the hose connection broken off. Restore the system or cap the fitting to prevent dirt from being drawn inside. Switches are available here, currently the website is being updated. I have repaired switches with a custom made aluminum adapter. Thank you. Will be looking for switch momentarily. Share this post Link to post Share on other sites
WHX?? 46,399 #6 Posted November 29, 2018 (edited) On all three of my 520's none ever worked and I doubt they ever will as I regularly service the filters. Two have the hose nipple broken off so Lynn is correct. Even tried to epoxy them back on but the switch was shot. I can see the thinking behind them tho the way those Onan's inhale air and grass clippings. Edited November 29, 2018 by WHX21 1 Share this post Link to post Share on other sites
formariz 11,849 #7 Posted November 29, 2018 Little by little I am digging into this tractor and learning about it. It certainly is not simple like the older ones. Pretty sophisticated wiring and thinking behind it. I can see why they are famous for electrical gremlins. 3 Share this post Link to post Share on other sites
lynnmor 6,698 #8 Posted November 29, 2018 I only had the warning light one time on one tractor. The paper filter was clogged with fine dust that got thru the pre-filter. I too, service the air filters often and was surprised that air flow was restricted so much on a filter that didn't look too bad. Only by holding the filter up to a light and comparing to a new one was the extent of dirt loading apparent. 2 Share this post Link to post Share on other sites
WHX?? 46,399 #9 Posted November 29, 2018 18 hours ago, formariz said: Shop tip here Cas .... close that choke plate any time you have it opened up. You do not want to drop errant hardware down there! 1 2 Share this post Link to post Share on other sites
cleat 4,893 #10 Posted November 29, 2018 Yes, I also do that on any engine with a vertical carb that can collect small parts. 1 Share this post Link to post Share on other sites
formariz 11,849 #11 Posted November 29, 2018 Great advice. Not used to this one yet. Its the only one with a vertical carb I have. Thank you guys. Share this post Link to post Share on other sites