520 Surge Issues

That is real interesting, in every lean case a little choking fixes that type of stuff. It is really good news to hear though!

Yeah the choke definitely didn't do anything for me in this case. I was really sweating over this one. For some reason I thought surge was related to valve seat...so glad that wasn't the case here. The tractor got a good once over though lol. Thanks for taking time out of your already busy day. I am thankful for everyone's help.

It is due for a valve adjustment at 500 hours also, sooner is usually better.

Good job Jeff, that should cure the overheating as well

Valve seating problems don't normally cause an engine to surge, it can, but 99% of the time it isn't. In my small experience, surging (with that much compression) is only caused by fuel problem, like clogged jet, fuel line, pump, sometimes filter. If the valves aren't seating, then it will only have like 40ish psi (remember that some engines, especially the Kohlers, have compression release on the exhaust valve). And it will be hard to start, if it does start it will be weak/sluggish.