Advice for non starting mower

[Burnerman]

The red arrow is pointing to the governor wheel which is driven by the camshaft. As it spins, it forces the end of it into contact with the lever that can be seen in your second picture. It looks to be correct from what I can see.
Did you see the lobes of the cam that actually lift the valves - not visible in the first pic?
John

 

[ipbr21054]

The lobes are like pear drop shape and dont look chipped or broken.

I assume i can silicone the sump up now

 

[Burnerman]

Yep, that's about right. There wasn't any other mechanism connecting to the exhaust cam lobe was there? If there was an automatic decompressor, this is where it would be.
John

 

[ipbr21054]

Nope
Just the wheel that connects to the arm in the other halh.
Plastic cam and 2 tappets

 

[Burnerman]

OK, pop the thing back together again, check it's free to rotate at every step and during the tightening up sequence.
(My head seems ready to explode now....)
John

 

[Burnerman]

Another thing.....when it's back together and you can spin the engine over.....
When each valve is fully closed there should be a tiny gap between the valve stem and the tappet - around 10 thou of an inch is fine.
Can you check this?
John

 

[ipbr21054]

Yes but will be Tuesday now.

 

[Old Salt]

Are all the teeth firm, not cracked or broken. Even a minute crack could open up when used in anger.

 

[Burnerman]

I'm really intrigued by the video in post #47 where the exhaust valve opens, then closes and momentarily opens a bit again.....to me this has to be an unusual camshaft profile, or the valve is somehow being interfered with by something else.
I realise that even the cam lobes are nylon but even so I've never come across a worn one.
John

 

[ipbr21054]

Unless for some reason the plastic cam gear for a split second goes backwards & opens again ?

 

[Burnerman]

Who knows - I would have expected any fractured gear wheel to fail completely as the teeth would jump out of mesh.
John