I recently purchased a 1997 JD345 with the 18hp Kawasaki FD590V. I was told the "plastic" cam gear was replaced when the engine was overhauled (when unknown) & the carb was replaced before I purchased it as it sat for a while and the old one was gunked up. The hours meter shows 2,200, but the guy I bought it from thought someone left the ignition on and ran it up. It's in decent shape overall so who knows.
Anyway. The tractor ran great when I bought it but I've been having some issues since. I started experiencing engine surge halfway through my first mow, which was in 90 degree heat and mowing some pretty tall grass/weeds, don't think it overheated though... This surge typically does NOT occur at full throttle, sometimes when not moving, but almost never while in motion or with the deck engaged (runs better with a load on the engine).
I did some regular maintenance items (fuel filter, air filter, spark plugs and a plug cap) in hopes it would correct the issue, but it continues. I sprayed some carb cleaner down the carb while running it a bit and it did seem to reduce the surge issue during that run. I am getting spark in both cylinders. Throttle/governor linkage/springs look to be in working order. It is tough to engage the choke (push throttle past full position style) and noticed the throttle cable has some tape on it towards the throttle lever. I am running 89 octane w/o ethanol and put stabil in fuel b/c I'm only using this to mow every other week or so.
Additionally my battery light started to turn on, and typically more so when at lower throttle. I tested the battery and it's fine. I did a quick mow around the pond this morning and both issues persist, started kinda rough and wanted to die with the throttle below 2nd from the top position.. Rain chased me off from attempting any additional troubleshooting.
I've read the battery light indicates a charging issue (not battery) so I know I need to check the voltage regulator next, ~14.5V? Could these issues be related? I'm open to suggestions on what to do next regarding the engine surge. Could the carb jets be gummed up already? Related to throttle cable? Valve adjustment? Vacuum leak?