1989520HC 13 #1 Posted March 21, 2015 Going to look at a 520 tomorrow. Guy says it surges at idle. If you pull the choke on a little it stops. I would think it is lean? Will a carb kit fix this or does the throttle shaft get so worn it starts running lean? Are the newer Onans any better. This is a 95. Anything else I should look at? Share this post Link to post Share on other sites
varosd 1,185 #2 Posted March 21, 2015 Most likely it's just a dirty carb...any pictures? 2 Share this post Link to post Share on other sites
1989520HC 13 #3 Posted March 21, 2015 Did they improve the motors any in later years? Better valve seats? How hard to find a carb kit? Share this post Link to post Share on other sites
lynnmor 6,796 #4 Posted March 22, 2015 I don't think the motors changed, but the carbs got worse as they changed them for emissions. There are cheap carb kits on ebay, but the needles don't work smoothly and the intake gaskets turn to mush in a year. You might check with onanparts.com for parts, you probably only need the basic carb and intake gaskets. 1 Share this post Link to post Share on other sites
ericj 1,576 #5 Posted March 22, 2015 take the top of the carb and clean it. the onan manual which you can down load on here will walk you through it. pull the jets out and clean the bowl area put it back together and fire it up no new parts needed only optional. i've clean a lot of these carbs and haven't had to buy parts to do it. have had to on rare occasion swap parts or carbs because i couldn't get them clean, but if i had a ultra sonic cleaner........ as far as the valve seats clean the block fins and block real good and adjust the valves and you should be golden eric j 3 Share this post Link to post Share on other sites
1989520HC 13 #6 Posted March 22, 2015 It has around 900 hours on it. Share this post Link to post Share on other sites
