Jgoodsell 19 #1 Posted October 25, 2017 I have a 518 with about 720 hours on it. The valves were adjusted at the beginning of summer, and hydro was replaced with an eaton 1100, fresh tune up including all fluids, plugs, oil filter, and fuel filter. She runs fine with no smoke at start and I can mow flat lawn for about 20 minutes before she starts to stutter. if you turn off the mower it gets better and you can mow again for a few minutes before it starts to stutter again. Now, I don't want to push my luck so I parked it and haven't done this more than 3 times now just to be sure it wasn't bad gas or a fluke. any suggestions on what this issue could be? Possible that the valve are out of adjustment again and need to be reseated? Share this post Link to post Share on other sites
Pollack Pete 2,273 #2 Posted October 25, 2017 I would drain the gas,put in all new rubber fuel lines,check the screen on the fuel tank pet cock.Fill with fresh,non-ethanol gas,put in maybe like 12 oz. of seafoam and try it out again.Without seeing the tractor,it sounds like a fuel problem to me.Also make sure the fuel cap vent is operational. 3 1 Share this post Link to post Share on other sites
ericj 1,576 #3 Posted October 25, 2017 did it run okay after doing all of the work ? or has it developed this problem after doing the work ? What do you call stuttering ? You could try to loosening the gas cap when it does that. You could recheck the valves,but they should haven't moved. Pete typed faster then me. good luck eric j 2 Share this post Link to post Share on other sites
Jgoodsell 19 #4 Posted October 30, 2017 To all, it was working great all winter and summer until recent. I never thought to check the gas cap. I will check that and the fuel tank pet cock was replaced when all the other maintenance was done because it was leaking. I will update you all as soon as I can. 1 Share this post Link to post Share on other sites
scotty 252 #5 Posted October 30, 2017 I had a 416h that would run good cold then it would start to surge when it got warmed up. It ended up being the float in the carb. 1 Share this post Link to post Share on other sites
953 nut 51,720 #6 Posted October 30, 2017 A couple of new spark plugs may help too. Share this post Link to post Share on other sites