littleredrider 408 #1 Posted February 26, 2018 Picked up a pretty clean 520 last Friday. Pretty sure it popped a valve seat. Haven’t torn it down yet, but when I do what i need? Is there a seal/gasket set or just new head gaskets? Anything I should do or look for when I’m in there? Share this post Link to post Share on other sites
Shynon 7,427 #2 Posted February 26, 2018 @boomers_influence will hook you up with everything you need, for a lot less than Toro. He took care of me when I needed help Share this post Link to post Share on other sites
richmondred01 2,190 #3 Posted March 4, 2018 (edited) https://www.onanparts.com/index.php?main_page=product_info&cPath=1_7_19&products_id=18 https://www.onanparts.com/index.php?main_page=product_info&cPath=1_8&products_id=32 These are the gaskets for the decarb operation. if the valve seat needs to be replaced that will open up an entire different can of worms. If so get your wallet ready. Onan parts aren’t cheap. When I did the valve seats I would tear the entire engine down to the bare block. Very costly. I don’t do them anymore because of the cost of the parts. Edited March 4, 2018 by richmondred01 Share this post Link to post Share on other sites
refracman 166 #4 Posted March 4, 2018 My engine guy does at least 3 or 4 a yr. The place local to me all you need to do is take the heads/ intake /exhaust and flywheel off. They charged him $100 for the last one. 2 Share this post Link to post Share on other sites
ericj 1,576 #5 Posted March 5, 2018 (edited) 6 hours ago, refracman said: My engine guy does at least 3 or 4 a yr. The place local to me all you need to do is take the heads/ intake /exhaust and flywheel off. They charged him $100 for the last one. I've been doing about 1 a year for about $ 100.00 also, using a local NAPA store that has a machine shop out back, never had any problems with them after, but haven't worked any real hard either. Thet custom grind a new seat to get correct fit. I get my parts from either boomer's influence or onan parts.com eric j Edited March 5, 2018 by ericj Share this post Link to post Share on other sites