Goat 2141 5 #1 Posted February 19, 2019 After the motor is running 30 minutes the engine starts to surging. How can fix this. Share this post Link to post Share on other sites
lynnmor 7,825 #2 Posted February 19, 2019 When you say surging, do you mean that it speeds up? If so, that is a governor problem. If you choke it a bit, does the surging diminish? If so, that is a carb or intake problem. Give a more detailed explanation and we can the narrow down the problem. 1 Share this post Link to post Share on other sites
WHX?? 51,782 #3 Posted February 19, 2019 Age old problem here goat, do a search on 520 or Onan surging and you will find a bunch of causes & fixes. Most commons dirty carb, leaking intake manifold or gov issues. 1 Share this post Link to post Share on other sites
Goat 2141 5 #4 Posted February 19, 2019 It goes up and d o wn when add choke it about the same Share this post Link to post Share on other sites
Ed Kennell 42,047 #5 Posted February 19, 2019 I cleaned the carb 3 times on my 520 before it stopped surging. 1 1 Share this post Link to post Share on other sites
lynnmor 7,825 #6 Posted February 19, 2019 50 minutes ago, Goat 2141 said: It goes up and d o wn when add choke it about the same You need to provide more information. Does it over speed when it is fully warmed up? Is the welch plug in place that is located just above the idle mixture screw? Does the engine run smoothly at idle? Have you had the carb off? Share this post Link to post Share on other sites
daveoman1966 3,841 #7 Posted February 20, 2019 Take the top off of carb and THOROUGHLY clean it out with carb cleaner and air blast. Caution on this needle valve.. Befor you take the top off, get a few pics of how all the linkages and such fit together. 1 1 Share this post Link to post Share on other sites
Goat 2141 5 #8 Posted February 20, 2019 Does not over speed when it warm up and I have had the carb off in a yr. Share this post Link to post Share on other sites
lynnmor 7,825 #9 Posted February 20, 2019 I would pull the intake and carb, then check the intake gaskets as well as the split line for leaks. Disassemble the carb, clean completely and set the float level. Use only Onan brand gaskets where the intake meets the engine block. With the intake off, it would be a good time to adjust the valves. Share this post Link to post Share on other sites
Reel Mower Freak 125 #10 Posted February 20, 2019 9 hours ago, daveoman1966 said: Take the top off of carb and THOROUGHLY clean it out with carb cleaner and air blast. Caution on this needle valve.. Befor you take the top off, get a few pics of how all the linkages and such fit together. When reassembling the carb, how does the needle valve go back in? Great pics for those of us with surging issues. Thanks. Share this post Link to post Share on other sites
