Deere X728 question
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crazyal
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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
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Crazyal....that is what I was thinking. The de-compression mechanism rattling because the rpm is slowing lower than running speed.
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.
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.
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!
Mike.
EDIT I meant to say camshaft in my description above!
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ruffdog
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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 LZ27LKA6 4 6 " Lazer Z Kawasaki FD75 D 27hp Engine Camshaft | eBay
eXmark LZ27LKA6 4 6 " Lazer Z Kawasaki FD75 D 27hp Engine Camshaft | eBay
Yes my mistake, I meant to say camshaft and not crankshaft. I made a correction to the OP.
Mike.
ruffdog
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And yes, I have heard it before.....happy mowing!
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.
Mike.
ruffdog
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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.