Deere X728 question

[mikefamig]

I have a John Deere X728 with Kawasaki FD750D 27hp engine. When I turn the key off at idle the engine naturally rotates a few last times before stopping but it makes a clanking or clicking sound duringthose last few revolutions.

I had two dealers listen to the machine and they both tell me that it is normal and that they all do that. Can you guys confirm this with your machines? Does your X700 machine do this?

I also have a Gravely zero turn mower with a smaller air cooled kawi engine and it also makes a ticking sound when stopping. It is not as loud as the Deere but it is there.

Mike.

 

[Richard001]

Mike,
If the dealer says it's not a problem then I guess I would not worry about it. You should be wearing hearing protection when operating the equipment, so leave your hearing protection on until the engine stops turning, then you woun't hear it.

Richard

 

[mikefamig]

Mike,
If the dealer says it's not a problem then I guess I would not worry about it. You should be wearing hearing protection when operating the equipment, so leave your hearing protection on until the engine stops turning, then you woun't hear it.

Richard

Being a machinist/mechanic it's hard to ignore.

Mike.

 

[mikefamig]

Mike,
If the dealer says it's not a problem then I guess I would not worry about it. You should be wearing hearing protection when operating the equipment, so leave your hearing protection on until the engine stops turning, then you woun't hear it.

Richard

This is exactly what I've done so far and plan to do in the future but until I know what is making the noise I won't be comfortable. I'm concerned that something will break in the engine and do more damage that was avoidable.

Mike.

 

[beenthere]

Maybe need to check the valve lash.

Only can guess what you are hearing.

 

[mercdv]

Kind of hard for people to tell what you are describing without you posting a video. You should record a short video and upload it to Youtube so people can hear what you are talking about. Not all of us own a X700 series but there are a lot of people here that know engines and can provide some advice off of what they hear int he video.

 

[mikefamig]

Kind of hard for people to tell what you are describing without you posting a video. You should record a short video and upload it to Youtube so people can hear what you are talking about. Not all of us own a X700 series but there are a lot of people here that know engines and can provide some advice off of what they hear int he video.

I am uploading a couple of videos now that will appear here shortly. Sorry for the delay but I've been busy and the holiday weekend came and here we are. I'd appreciate any feedback. I'd especially like to see avideo of other a700 engines that do or don't make the same noise.

Mike.

 

[mikefamig]

Here is a video of the noise. Listen to the last few revolutions after the ignition key is turned off and the engine comes to a halt.

John Deere X728 Kawasaki FD75D 27hp engine noise - YouTube

Mike.

 

[mikefamig]

This is what it sounds like when I twist the drive-shaft and snap it back and forth with my hand.

IMG ��8�1 - YouTube

Mike.

 

[mikefamig]

Understand that I have removed the drive-shaft and fan belt and the noise is the same. I have run the engine with the valve covers removed. I held a thumb on each rocker arm with the engine running and there is no change in the noise. I have also removed the spark plugs and used a wooden rod to push down on the piston as the driveshaft is twisted back and forth and there is no change in the noise.

I do not believe that it is in the valve train or crankshaft/pistons. It is a tinny noise in the front of the engine.

Mike.

 

[mikefamig]

Can anyone tell me that their X700 series or any horizontal kawasaki engine does or doesn't make this clacking noise as it comes to a halt?

Mike.

 

[crazyal]

I don't know about that engine but I've had several that have a weight system inside the engine. When the engine isn't running springs keep a lever in place to slightly keep the exhaust valve open to make starting easier. Once the engine starts to spin the lever moves out of the way so the engine can run correctly. You could be hearing it resetting as the engine slows down.

 

[ruffdog]

Crazyal....that is what I was thinking. The de-compression mechanism rattling because the rpm is slowing lower than running speed.

 

[mikefamig]

First thanks both for the reply. Crazyal what you say makes sense and I'd love to think that this is what's going on. It would also explain the dealer saying that it's normal. I have the technical repair manual for the engine and haven't seen anything like this, where in the engine would it be located?

Is it normal or common for this compression release to have enough play in it to make noise? Have you guys heard this before?

Mike.

 

[mikefamig]

I just looked at the tech manual on the engine and there is something going on with the crankshaft that looks like a compression relief device. I'm having trouble finding a good photo of one but I'll keep looking. The noise seems to be coming from the crankcase cover on the front the engine where the cam gear is located.

Mike.

EDIT I meant to say camshaft in my description above!

 

[ruffdog]

Normally it is on the camshaft. There will be a spring loaded weight that swings out at a specified rpm. At cranking speed, the spring can hold the weight in that activates the device that slightly opens the exhaust valve. At running speed, the weight swings out and the valve train operates normally. Search fd750d camshaft for pictures:

eXmark LZ27LKA64 6" Lazer Z Kawasaki FD75D 27hp Engine Camshaft | eBay

 

[mikefamig]

Normally it is on the camshaft. There will be a spring loaded weight that swings out at a specified rpm. At cranking speed, the spring can hold the weight in that activates the device that slightly opens the exhaust valve. At running speed, the weight swings out and the valve train operates normally. Search fd750d camshaft for pictures:

eXmark LZ27LKA64 6" Lazer Z Kawasaki FD75D 27hp Engine Camshaft | eBay

Yes my mistake, I meant to say camshaft and not crankshaft. I made a correction to the OP.

Mike.

 

[ruffdog]

And yes, I have heard it before.....happy mowing!

 

[mikefamig]

Later today I plan to remove the valve covers and double-check my valve lash adjustment. I did adjust the valves not too long ago and it could be that closing the gap to .006 could have made the compression release mechanism a little noisier because it is lifting the exhaust valve a little higher and snapping back a little harder.

Mike.

 

[ruffdog]

With the OHV engines, it is important to check valve clearance so the compression release works properly. If the clearance is too loose, the valve doesn't open and the starter has to work hard to turn the engine over. The sound you hear is when the CR weight starts being pulled IN because the engine is lower than idle rpm, then the cam follower hits the compression release pin that then throws the weight back out to its limit. That is the click, click, click.