nekovt 0 #1 Posted May 23, 2012 Hello! I have been working on restoring a very neglected 520-8. I had it running great, I Was doing a test mow which worked for about 15 minutes and then it started idling up and down up and down and won't stop. If I choke it up a little bit, it will smooth out a little bit. It was low on gas, I filled it up and tried running it for a little bit but I don't want to run it for to long while it's doing that. After some work, I've checked/got: - Each Cyclinder compression is good - The manifold intake has been tightend down - Top air cleaner, etc taken apart and checked. - Two new spark plugs - Spark plug wires checked and reclamped. I'm guessing I have the regulator arm (the arm that moves back and forth above the fan) connected correctly. Has anyone ever run in to this problem? Thanks! BRad Share this post Link to post Share on other sites
Wheelhorse84 87 #2 Posted May 23, 2012 Carb needs a cleaning. Share this post Link to post Share on other sites
CRE1992 135 #3 Posted May 23, 2012 You need to take the carb off and then take it apart. Gunk Carb Cleaner in a gallon can is your best friend. Soak it overnight and reassemble. Then it should be good as new. Share this post Link to post Share on other sites
nekovt 0 #4 Posted May 24, 2012 I can certainly take it off and apart. Would it run fine for a while and just start doing this like a switch was flipped? Thanks! Share this post Link to post Share on other sites
nekovt 0 #5 Posted May 24, 2012 I took apart the top part of the carb. The float system and everything looks clean, but there's a lot of dirt or rust particles or something a the bottom of the float chamber. The fuel filter looks perfectly clean, any idea of where all this crap could have come from? Thanks! Share this post Link to post Share on other sites
varosd 1,185 #6 Posted May 24, 2012 clean the gas tank! I cleaned all sorts of junk out of mine and also changed the fuel filter. I only use high octane gas and never let it get to the bottom! Share this post Link to post Share on other sites
CRE1992 135 #7 Posted May 24, 2012 I took apart the top part of the carb. The float system and everything looks clean, but there's a lot of dirt or rust particles or something a the bottom of the float chamber. The fuel filter looks perfectly clean, any idea of where all this crap could have come from? Thanks! There is alot you cannot just clean by taking the top of the carb off. Trust me Ive had 4 onans. Take the carb off, take it apart, soak it over night put it back together and you should be good. I would also replace the fuel line and fuel filters. Share this post Link to post Share on other sites
can whlvr 991 #8 Posted May 24, 2012 crap allways seems to get by the filter,but at least you dont have the dreaded onan valve seat problem Share this post Link to post Share on other sites
nekovt 0 #9 Posted May 24, 2012 Thanks everyone! i've got the carb off, apart and soaking in seafoam over night. There was ALOT of stuff on the bottom of the float bowl. I looked at the filter, even though it looks clean, there's some fluid stuck at the top that won't come out. So there's something up there. Do the gas lines degrade over time and small pieces get in the Carb? I'll clean out the gas tank to. Thanks! Share this post Link to post Share on other sites
nekovt 0 #10 Posted May 24, 2012 One thing I forgot to mention, I took everything out of carb except for the jet that's on the side - there's a plastic guide that only lets you turn it half a turn. I'm guessing that it's a high speed jet? Share this post Link to post Share on other sites
