WH520 17 #1 Posted June 25, 2012 Today I decided it was time to adjust the valves on my 518. It just about has 1350 hours and I'm about 99% sure they've never been checked before. To my surprise they were just about in spec, varying 1-2 thousandths on the snug side. On to my question, Both of the intake ports look like they have been chewed up a little bit, and in the same spot on both sides.. I can't figure out why, can someone explain? Here's some pictures, sorry if they're hard to see. You can kind of see the shiny spot above the valve. Share this post Link to post Share on other sites
Docwheelhorse 2,561 #2 Posted June 25, 2012 If I had to venture an explanation it looks like the maching tool that cut the port "crashed" into the block at the end of the cutting stroke. I'm sure its harmless.... button it back up and get back on the race track! Tony Share this post Link to post Share on other sites
WH520 17 #3 Posted June 25, 2012 I was thinking something along those lines but wasn't sure. After hearing all the Onan horror stories with valves, I had to be sure Going to get new valve cover gaskets and intake gaskets tomorrow and button it back up. I'm still kind of excited that they weren't terribly tight with the hours that are on it. Little weight lifted off my chest. Share this post Link to post Share on other sites
WH520 17 #4 Posted June 25, 2012 It's all back together and sounds awesome. Now it sounds like my 520 did. Have to go get some new bolts for the mower deck and throw it back on. Then it will be time for the real test. Share this post Link to post Share on other sites
