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This is one of those cheap push mowers with a Briggs engine (3.75 hp). I am getting spark, and I have sprayed starter fluid directly into the carb. It will not start. What else can I try? It has an over the gas tank carb. I tried starting it without the air filter assembly as well. I have not checked compression yet. I did, however, remove the spark plug and pulled the starter rope. There was a lot more resistance when it was in. I do have a compression gauge. What should compression be on this engine?

What else could be causing it to not start?

Thanks

How did you check for spark? And was it a lot of spark?

sometimes a stuck valve will case this ...check compression

The spark was strong. I used a new spark plug. I tested it by pulling the starter rope with the plug removed (grounded). I could see the sparks.

What should the compression be? Is there anyway to get the valve to free up, or is it junk if the compression is low?

I was looking at Murray's website and it states that low oil can cause a no start issue. The air filter was saturated with oil, so it is probably a little low. Why does a low oil situation cause a mower not to start?


Edit:

It looks like there is a low oil switch on some mowers.

A cheapo with a Briggs flat head won't have that low oil sensor. If the air filter is oily, my guess is a bad valve seal. This is a seal around the valve stem that separates the crankcase from the combustion chamber.

check flywheel key make sure its ok

You should already have the low oil thing taken care of because you are supposed to check it before trying to start it. The air filter is more than likely oily because it is a oil type air filter. It is supposed to be that way in other words. It might help to read your book that comes with the mower. Then you will know how it works. That in itself will eliminate about half of your troubleshooting. Simple things can prevent those mowers from starting. Things like a dirty air filter for example. So can complicated things, like the rinky dinky plastic cam shaft gear spinning free on the metal shaft. Running them with No oil or low oil can prevent them from ever starting again. Better start from the basics. Then work into things like valves.

You need a spark tester to check for spark. Checking with a plug only shows a spark.
A spark tester checks the coil at full load as if under compression conditions.
I would say carb problem. Clean carb and fit 795083 diaphragm/ gasket set.

The engine didn't have compression. I removed the head and turned the flywheel nut manually. The valves do not open and close as they should. The odd thing is that if I turn the flywheel the wrong way (counterclockwise) the valves open and close. What do you think could be causing this problem? Camshaft?

One more thing I would like to add is that the mower was only run a couple of times. It is out of the warranty, however.