Click / knocking noise 09p702 0127-h1

[bertsmobile1]

Customer brought in a local push mower fitted with this 140cc engine complaining it had a tapping noise.
Previously it had been in for blades touching the baseplate which was beaten out.
Thought it was the same problem repeating but the blades are fine

When rotating the engine by hand I get a definate click from the ACR unit when the valve closes
Is this normal ?
I don't remember it doing this when it was serviced 3 years ago .
Would I be correct in diagnosing a deceased cam ?
Do these engines suffer abnormal cam problems ?
it is a 2016 build on an 18" mower with swing back blades & customer has a small domestic property about 1/6th acre with a big house so not much lawn.
Last year was the first set of blades & generally swing backs get replaced every 2 to 3 years so it has not done much work .

 

[tom3]

I'd think that comp. release would be out of the way when running. Plastic cam gears shot? If you get deeper into it let us know what you find.

 

[Rivets]

Two questions. Does the clicking increase and decrease with engine speed? Can you tell when it clicks by locating piston position through the spark plug opening? I’m wondering if you may have a sticking valve, snapping shut.

 

[bertsmobile1]

Told the customer that it would need to be pulled down but he is moving & does not want to go that far .
Clicks after the valve has closed and does not do it when the exhaust opens & closes normally , just after decompression which is why I suspected the cam.
And hes if I pull the starter rope it clicks a lot faster than when rotating slowly by turning the blade .
I don't get many of these engines in and when they do normally it is for carb problems.

 

[tom3]

If it still runs maybe tell him to use it until it quits. Might have a nice window in the block to see what was wrong?

 

[bertsmobile1]

Tom.
That is exactly where we are at.
He picked it up this morning .
I need to get my hands on some good EX series engines to see what they are like because at the moment I have no refference point to work from
Unforunately every one I see is stuffed and quite frankly they make little sense to me
That plastic carb seem to be total trash & the auto choke is a joke