When i picked up my mower from the dealer i noticed the koholer 23 comand motor had alot of tapping sound coming from it. I asked the dealer if it was noramal he said yes. i read the kohler manual it said it has hydraulic lifters and untill there built up they will tap. I have 75hours on the motor now.I noticed when i first start the mower at idle i can still hear tapping if i mow with it then bring it down to idle sometimes it stops. i guess the lifters are built up after use .I have a kohler 22 command motor on another ztr it does not make the tapping sound. I just wanted to know if this is normal for the kohler motors. also i noticed when i turn off the motor it pops or somtimes trys to keep runing. I let it idle for about 20 seconds befor truning it off. thanks shawn.