bomber19 2 #1 Posted May 18, 2012 Just mowing along yesterday and my 518 started surging, I cleaned the carb but that didn't help, any suggestions please?? Share this post Link to post Share on other sites
MalMac 1,328 #2 Posted May 18, 2012 It's still probably a dirty carb, check your fuel tank make sure you don't have a bunch a gunk in there. Check your fuel line to be sure it's not starting to disintegrate on you and allow small particles of rubber through. More than likely it's the carb. I had to clean one on my 520 three different times before it started acting right. There could be other issues but 95% of the time it's a dirty carb. Share this post Link to post Share on other sites
kpinnc 10,990 #3 Posted May 18, 2012 Did you take the carb apart and soak it, or just use a spray cleaner? The orifices in the jets are pretty small, and easily clogged. Running a little choke should help for a short time, but it won't fix anything. The engine may run hotter as well... Share this post Link to post Share on other sites
bomber19 2 #4 Posted May 18, 2012 Thanks for the replies, I'll try cleaning it again! Share this post Link to post Share on other sites
JackC 616 #5 Posted May 19, 2012 My 520HC is surging this year. Ran fine the two previous years. I assume the ethanol absorbed some moisture and gummed up a passage in the carburetor. Keep us posted on what you find. The ONAN manual says: "Carburetor problems that are not corrected by mixture adjustments are usually a result of gummed-up fuel passages or worn internal parts. The most effective solution is a carburetor overhaul. In general, overhauling a carburetor consists of disassembly, a thorough cleaning, and replacement of parts. Carburetor overhaul kits are available" Share this post Link to post Share on other sites
smoreau 658 #6 Posted May 19, 2012 Carb kits for onen engines are not cheep! I just take the top off and use a rag to dry out the bowel. then take the straw of my carb spray to make sure every passage is clear in the bottom part of the carb and the top. I also use compressed air to remove any deposits in the bowel. I have had good luck with this procedure so far and have not had to buy a overhaul kit yet. I also change the filter every year. Share this post Link to post Share on other sites
bomber19 2 #7 Posted May 19, 2012 Wow..I found the problem...while blowing the carb out , I must have blew out the welch plug above the mixture screw, found another plug and it runs fine now, so warning....be careful when blowing out the holes in the carb! Share this post Link to post Share on other sites
JackC 616 #8 Posted May 19, 2012 The no overhaul kit cleaning procedure sounds like a good idea. Keep it simple. I am going to give a try. Thanks Share this post Link to post Share on other sites
