have a john deere scots 2048 lawn tractor with kohler cv20s 20 h.p. ohv engine with excessive valve noise. info i,ve found indicates hydraulic lifters but no mention of any valve adjustment. also shows to have pressure lube oil system. need to know what oil pressure should be & if cks. ok am i looking at possible worn lifters, push rods, etc. any help or info greatly appreciated. thanks, jim
Might be time to remove the lifters and inspect, they could be gummed up and sticky, I cannot give you an oil pressure requirement of the engine and not sure where you would attach a test gauge on the engine, I would imagine if the engine oil pump was not up to spec, then you will eventually have a major engine problem.
With the tappet cover removed, you should be able to see if there is any major wear in the rockers and pushrods, the hydraulic lifters have an internal compression spring which is preset, the spring may have weakened or even broke, there is not much to go wrong with hydraulic lifters, as mentioned, gummed up or weak or broken spring.
You should be able to remove the lifters from their guides with one of those "Snap On telescopic magnet" or the like without having to remove the engine from the chassis and pull the engine down, make sure you reinsert each lifter into the correct inlet and exhaust crankcase guide on assembly.
