MTD push mower starts then stalls

[bertsmobile1]

The real deal Briggs compressor makes things a bit easier.
The inlet & exhaust have different retainers.
One has a keyhole in the spring colar so you just compress the spring a little then push it back .
You can do this with a pair of long pointy nose pliers, or a couple of thick screwdrivers or the V end of a wrecking bar.
The other will either have a pin or regular collets.
You can work around, just depends on how much time you have and what sort of educational event you wish to make of it.
I always replace gaskets, they are about $ 5.00 for the head gasket or $ 15 for the full kit.
Just like a car head, start from the centre and loosen off the bolts 1/6 turn each in a criss cross manner then a second 1/6 th turn by which time ther should be almost no tension in the bolts.
I face down the ends of the valves with an oil stone.
It is a little tedious but you don't overshoot then have to machine down the seats which are a lot harder to compensate.
Briggs give you a clearence both with springs and without springs and I generally find the maxium clearance without springs brings fairly well in the middle of the clearence range with springs.
Good luck.

 

[NBforge]

I cant tell you how much I appreciate you sharing the info, it makes the task a heck of a lot more approachable. For now we are waiting to get our spring compressor and gasket in the mail.

Managed to limp through getting the yard cut with the lawn boy I picked up but that too needs some TLC. I started with a new plug and sharpened blades but it still runs for a bit and then dies out. Im hoping a carb cleaning will get things right but the way that carb is stuffed in there is odd.

 

[NBforge]

In waiting for the spring compressor to arrive, the carb has been rebuilt and cleaned, fresh diaphragm. It looks like tomorrow will be the day to get going on everything.

For valve stem lubricant, do I really need to use one specific for mower engines? Or am I good just using a little of the oil I run in there?

 

[NBforge]

We have the valves and springs out. I had several questions at this point-

Is a green Scotch brite pad ok to use to clean the head and the valves?

The upper (intake) valve has a little resistance when you pull it out, is this ok? The valve is not bent, however I do see there is a little rubber collar sticking out of the chamber, whereas the other chamber this collar is flush with the opening. I am trying to attach pictures. Don't know if this is normal or not.

This valve had more carbon on it than the other so perhaps that too caused resistance.

I have only been able to find clearance specs with springs, any idea where to find them without? Model 09S0502 code 0520

Lastly, how free should the engine turn? It feels pretty firm in my option and stiffens as the piston reaches the top of the cylinder.


The first picture is the lower chamber and the second is the upper with the rubber collar sticking out